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Full-Text Articles in Physics

Measurement Of Charm And Bottom Production From Semileptonic Hadron Decays In P + P Collisions At √S = 200 Gev, C. Aidala, Nicole J. Apadula, John C. Hill, Nels J. Hotvedt, John G. Lajoie, Alexandre Lebedev, S. H. Lee, Craig Ogilvie, Milap R. Patel, Joshua Perry, Timothy T. Rinn, Marzia Rosati, Jonathan C. Runchey, Abhisek Sen, M. Shimomura, Arbin Timilsina, Yunxiao Zhai, Et Al., Phenix Collaboration May 2019

Measurement Of Charm And Bottom Production From Semileptonic Hadron Decays In P + P Collisions At √S = 200 Gev, C. Aidala, Nicole J. Apadula, John C. Hill, Nels J. Hotvedt, John G. Lajoie, Alexandre Lebedev, S. H. Lee, Craig Ogilvie, Milap R. Patel, Joshua Perry, Timothy T. Rinn, Marzia Rosati, Jonathan C. Runchey, Abhisek Sen, M. Shimomura, Arbin Timilsina, Yunxiao Zhai, Et Al., Phenix Collaboration

Physics and Astronomy Publications

Measurements of the differential production of electrons from open-heavy-flavor hadrons with charm- and bottom-quark content in p+p collisions at √s=200  GeV are presented. The measurements proceed through displaced-vertex analyses of electron tracks from the semileptonic decay of charm and bottom hadrons using the PHENIX silicon-vertex detector. The relative contribution of electrons from bottom decays to inclusive heavy-flavor-electron production is found to be consistent with fixed-order-plus-next-to-leading-log perturbative-QCD calculations within experimental and theoretical uncertainties. These new measurements in p+p collisions provide a precision baseline for comparable forthcoming measurements in A+A collisions.


Measurements Of Μμ Pairs From Open Heavy Flavor And Drell-Yan In P + P Collisions At √S = 200 Gev, C. Aidala, Nicole J. Apadula, John C. Hill, Nels J. Hotvedt, John G. Lajoie, Alexandre Lebedev, S. H. Lee, Craig Ogilvie, Milap R. Patel, Joshua Perry, Timothy T. Rinn, Marzia Rosati, Jonathan C. Runchey, Abhisek Sen, M. Shimomura, Arbin Timilsina, Et Al., Phenix Collaboration Apr 2019

Measurements Of Μμ Pairs From Open Heavy Flavor And Drell-Yan In P + P Collisions At √S = 200 Gev, C. Aidala, Nicole J. Apadula, John C. Hill, Nels J. Hotvedt, John G. Lajoie, Alexandre Lebedev, S. H. Lee, Craig Ogilvie, Milap R. Patel, Joshua Perry, Timothy T. Rinn, Marzia Rosati, Jonathan C. Runchey, Abhisek Sen, M. Shimomura, Arbin Timilsina, Et Al., Phenix Collaboration

Physics and Astronomy Publications

PHENIX reports differential cross sections of mu mu pairs from semileptonic heavy-flavor decays and the Drell-Yan production mechanism measured in p + p collisions at root s = 200 GeV at forward and backward rapidity (1.2 < vertical bar eta vertical bar < 2.2). The mu mu pairs from c (c) over bar, b (b) over bar, and Drell-Yan are separated using a template fit to unlike- and like-sign muon pair spectra in mass and p(T). The azimuthal opening angle correlation between the muons from c (c ) over bar and b (b) over bar decays and the pair-p(T) distributions are compared to distributions generated using PYTHIA and POWHEG models, which both include next-to-leading order processes. The measured distributions for pairs from a are consistent with PYTHIA calculations. The c (c) over bar data present narrower azimuthal correlations and softer p(T) distributions compared to distributions generated from POWHEG. The b (b ) over bar data are well described by both models. The extrapolated total cross section for bottom production is 3.75 +/- 0.24(stat) +/-(0.35)(0.50) (syst) +/- 0.45(global) [mu b], which is consistent with previous measurements at the Relativistic Heavy Ion Collider in the same system at the same collision energy and is approximately a factor of 2 higher than the central value calculated with theoretical models. The measured Drell-Yan cross section is in good agreement with next-to-leading-order quantum-chromodynamics calculations.


Creation Of Quark–Gluon Plasma Droplets With Three Distinct Geometries, C. Aidala, Nicole J. Apadula, John C. Hill, Nels J. Hotvedt, John G. Lajoie, Alexandre Lebedev, S. H. Lee, Craig Ogilvie, Milap R. Patel, Joshua Perry, Timothy T. Rinn, Marzia Rosati, Jonathan C. Runchey, Abhisek Sen, M. Shimomura, Arbin Timilsina, Et Al., Phenix Collaboration Mar 2019

Creation Of Quark–Gluon Plasma Droplets With Three Distinct Geometries, C. Aidala, Nicole J. Apadula, John C. Hill, Nels J. Hotvedt, John G. Lajoie, Alexandre Lebedev, S. H. Lee, Craig Ogilvie, Milap R. Patel, Joshua Perry, Timothy T. Rinn, Marzia Rosati, Jonathan C. Runchey, Abhisek Sen, M. Shimomura, Arbin Timilsina, Et Al., Phenix Collaboration

Physics and Astronomy Publications

Experimental studies of the collisions of heavy nuclei at relativistic energies have established the properties of the quark–gluon plasma (QGP), a state of hot, dense nuclear matter in which quarks and gluons are not bound into hadrons 1–4 . In this state, matter behaves as a nearly inviscid fluid 5 that efficiently translates initial spatial anisotropies into correlated momentum anisotropies among the particles produced, creating a common velocity field pattern known as collective flow. In recent years, comparable momentum anisotropies have been measured in small-system proton–proton (p+p) and proton–nucleus (p+A) collisions, despite expectations that the ...


Chiral Cherenkov And Chiral Transition Radiation In Anisotropic Matter, Kirill Tuchin Dec 2018

Chiral Cherenkov And Chiral Transition Radiation In Anisotropic Matter, Kirill Tuchin

Physics and Astronomy Publications

A significant contribution to the electromagnetic radiation by a fast electric charge moving in anisotropic chiral matter arises from spontaneous photon radiation due to the chiral anomaly. While such a process, also known as the “vacuum Cherenkov radiation,” is forbidden in the QED vacuum, it can occur in chiral matter, where it is more appropriate to call it the “chiral Cherenkov radiation.” Its contribution to the radiation spectrum is of order α2 compared to α3 of the bremsstrahlung. I derive the frequency spectrum and the angular distribution of this radiation in the high energy limit. The quantum effects ...


Radiative Instability Of Quantum Electrodynamics In Chiral Matter, Kirill Tuchin Nov 2018

Radiative Instability Of Quantum Electrodynamics In Chiral Matter, Kirill Tuchin

Physics and Astronomy Publications

Modification of the photon dispersion relation in chiral matter enables 1 -> 2 scattering. As a result, the single fermion and photon states are unstable to photon radiation and pair production respectively. In particular, a fast fermion moving through chiral matter can spontaneously radiate a photon, while a photon can spontaneously radiate a fast fermion and anti-fermion pair. The corresponding spectra are derived in the ultra-relativistic approximation. It is shown that the polarization of the produced and decayed photons is determined by the sign of the chiral conductivity. Impact of a flat thin domain wall on the spectra is computed.


Transition Radiation As A Probe Of The Chiral Anomaly, Xu-Guang Huang, Kirill Tuchin Nov 2018

Transition Radiation As A Probe Of The Chiral Anomaly, Xu-Guang Huang, Kirill Tuchin

Physics and Astronomy Publications

A fast charged particle crossing the boundary between chiral matter and vacuum radiates transition radiation. Its most remarkable features—the resonant behavior at a certain emission angle and the circular polarization of the spectrum—depend on the parameters of the chiral anomaly in a particular material or matter. Chiral transition radiation can be used to investigate the chiral anomaly in such diverse media as the quark-gluon plasma, Weyl semimetals, and axionic dark matter.


Pseudorapidity Dependence Of Particle Production And Elliptic Flow In Asymmetric Nuclear Collisions Of P + Al, P + Au, D + Au, And 3he + Au At √Snn = 200 Gev, A. Adare, Nicole J. Apadula, Sarah C. Campbell, John C. Hill, Nels J. Hotvedt, John G. Lajoie, Alexandre Lebedev, S. H. Lee, Craig Ogilvie, Milap R. Patel, Joshua Perry, Timothy T. Rinn, Marzia Rosati, Jonathan C. Runchey, Abhisek Sen, M. Shimomura, Arbin Timilsina, Et Al., Phenix Collaboration Nov 2018

Pseudorapidity Dependence Of Particle Production And Elliptic Flow In Asymmetric Nuclear Collisions Of P + Al, P + Au, D + Au, And 3he + Au At √Snn = 200 Gev, A. Adare, Nicole J. Apadula, Sarah C. Campbell, John C. Hill, Nels J. Hotvedt, John G. Lajoie, Alexandre Lebedev, S. H. Lee, Craig Ogilvie, Milap R. Patel, Joshua Perry, Timothy T. Rinn, Marzia Rosati, Jonathan C. Runchey, Abhisek Sen, M. Shimomura, Arbin Timilsina, Et Al., Phenix Collaboration

Physics and Astronomy Publications

Asymmetric nuclear collisions of p+Al, p+Au, d+Au, and 3He+Au at √sNN=200  GeV provide an excellent laboratory for understanding particle production, as well as exploring interactions among these particles after their initial creation in the collision. We present measurements of charged hadron production dNch/dη in all such collision systems over a broad pseudorapidity range and as a function of collision multiplicity. A simple wounded quark model is remarkably successful at describing the full data set. We also measure the elliptic flow v2 over a similarly broad pseudorapidity range. These measurements provide key constraints on models ...


Measurement Of Φ-Meson Production At Forward Rapidity In P+P Collisions At √S=510 Gev And Its Energy Dependence From √S=200 Gev To 7 Tev, A. Adare, Nicole J. Apadula, Sarah C. Campbell, Lei Ding, John C. Hill, Nels J. Hotvedt, John G. Lajoie, Alexandre Lebedev, S. H. Lee, Craig Ogilvie, Milap R. Patel, Joshua Perry, Timothy T. Rinn, Marzia Rosati, Jonathan C. Runchey, Abhisek Sen, M. Shimomura, Arbin Timilsina, Shawn Whitaker, Et Al., Phenix Collaboration Nov 2018

Measurement Of Φ-Meson Production At Forward Rapidity In P+P Collisions At √S=510 Gev And Its Energy Dependence From √S=200 Gev To 7 Tev, A. Adare, Nicole J. Apadula, Sarah C. Campbell, Lei Ding, John C. Hill, Nels J. Hotvedt, John G. Lajoie, Alexandre Lebedev, S. H. Lee, Craig Ogilvie, Milap R. Patel, Joshua Perry, Timothy T. Rinn, Marzia Rosati, Jonathan C. Runchey, Abhisek Sen, M. Shimomura, Arbin Timilsina, Shawn Whitaker, Et Al., Phenix Collaboration

Physics and Astronomy Publications

The PHENIX experiment at the Relativistic Heavy Ion Collider has measured the differential cross section of phi(1020)-meson production at forward rapidity in p + p collisions at root s = 510 GeV via the dimuon decay channel. The partial cross section in the rapidity and P-T ranges 1.2 < vertical bar y vertical bar < 2.2 and 2 < p(T) < 7 GeV/c is sigma(phi) = [2.28 +/- 0.09(stat) +/- 0.14(syst) +/- 0.27(norm)] x 10(-2) mb. The energy dependence of sigma(phi) (1.2 < vertical bar y vertical bar < 2.2,2 < p(T) < 5 GeV/c) is studied using the PHENIX measurements at root s = 200 and 510 GeV and the Large Hadron Collider measurements atroot s = 2.76 and 7 TeV. The experimental results arc compared to various event generator predictions (PYTHIA6, PYTHIA8, PHOJET, AMPT, EPOS3, and EPOS-LHC).


Cross Section And Longitudinal Single-Spin Asymmetry Al For Forward W± → Μ±Ν Production In Polarized P+P Collisions At √S=510 Gev, A. Adare, Nicole J. Apadula, Sarah C. Campbell, Lei Ding, John C. Hill, Nels J. Hotvedt, John G. Lajoie, Alexandre Lebedev, S. H. Lee, Craig Ogilvie, Milap R. Patel, Joshua Perry, Timothy T. Rinn, Marzia Rosati, Jonathan C. Runchey, Abhisek Sen, Alex Shaver, M. Shimomura, Arbin Timilsina, Shawn Whitaker, Et Al., Phenix Collaboration Aug 2018

Cross Section And Longitudinal Single-Spin Asymmetry Al For Forward W± → Μ±Ν Production In Polarized P+P Collisions At √S=510 Gev, A. Adare, Nicole J. Apadula, Sarah C. Campbell, Lei Ding, John C. Hill, Nels J. Hotvedt, John G. Lajoie, Alexandre Lebedev, S. H. Lee, Craig Ogilvie, Milap R. Patel, Joshua Perry, Timothy T. Rinn, Marzia Rosati, Jonathan C. Runchey, Abhisek Sen, Alex Shaver, M. Shimomura, Arbin Timilsina, Shawn Whitaker, Et Al., Phenix Collaboration

Physics and Astronomy Publications

We have measured the cross section and single-spin asymmetries from forward W±→μ±ν production in longitudinally polarized p+p collisions at √s=510  GeV using the PHENIX detector at the Relativistic Heavy Ion Collider. The cross sections are consistent with previous measurements at this collision energy, while the most forward and backward longitudinal single spin asymmetries provide new insights into the sea quark helicities in the proton. The charge of the W bosons provides a natural flavor separation of the participating partons.


Single-Spin Asymmetry Of J/Ψ Production In P+P, P+Al, And P+Au Collisions With Transversely Polarized Proton Beams At √Snn=200 Gev, C. Aidala, Nicole J. Apadula, John C. Hill, Nels J. Hotvedt, John G. Lajoie, Alexandre Lebedev, S. H. Lee, Craig Ogilvie, Milap R. Patel, Joshua Perry, Timothy T. Rinn, Marzia Rosati, Jonathan C. Runchey, Abhisek Sen, M. Shimomura, Arbin Timilsina, Et Al., Phenix Collaboration Jul 2018

Single-Spin Asymmetry Of J/Ψ Production In P+P, P+Al, And P+Au Collisions With Transversely Polarized Proton Beams At √Snn=200 Gev, C. Aidala, Nicole J. Apadula, John C. Hill, Nels J. Hotvedt, John G. Lajoie, Alexandre Lebedev, S. H. Lee, Craig Ogilvie, Milap R. Patel, Joshua Perry, Timothy T. Rinn, Marzia Rosati, Jonathan C. Runchey, Abhisek Sen, M. Shimomura, Arbin Timilsina, Et Al., Phenix Collaboration

Physics and Astronomy Publications

We report the transverse single-spin asymmetries of J/ψ production at forward and backward rapidity, 1.2<|y|<2.2, as a function of J/ψ transverse momentum (pT) and Feynman-x (xF). The data analyzed were recorded by the PHENIX experiment at the Relativistic Heavy Ion Collider in 2015 from p+p, p+Al, and p+Au collisions with transversely polarized proton beams at √sNN=200  GeV. At this collision energy, single-spin asymmetries for heavy-flavor particle production of p+p collisions provide access to the spin-dependent gluon distribution and higher-twist correlation functions inside the nucleon, such as the gluon Qiu-Sterman and trigluon correlation functions. Proton+nucleus collisions offer an excellent opportunity to study nuclear effects on the correlation functions. The data indicate a positive asymmetry at the two-standard-deviation level in the p+p data for 2  GeV/c


Cross Section And Transverse Single-Spin Asymmetry Of Muons From Open Heavy-Flavor Decays In Polarized P Plus P Collisions At Root S=200 Gev, C. Aidala, Nicole Apadula, Sarah C. Campbell, Lei Ding, John C. Hill, Nels J. Hotvedt, John G. Lajoie, Alexandre Lebedev, Craig Ogilvie, Milap R. Patel, Joshua Perry, Timothy T. Rinn, Marzia Rosati, Jonathan C. Runchey, Abhisek Sen, Alex Shaver, M. Shimomura, Arbin Timilsina, Shawn Douglas Whitaker, Et Al., Phenix Collaboration Jun 2017

Cross Section And Transverse Single-Spin Asymmetry Of Muons From Open Heavy-Flavor Decays In Polarized P Plus P Collisions At Root S=200 Gev, C. Aidala, Nicole Apadula, Sarah C. Campbell, Lei Ding, John C. Hill, Nels J. Hotvedt, John G. Lajoie, Alexandre Lebedev, Craig Ogilvie, Milap R. Patel, Joshua Perry, Timothy T. Rinn, Marzia Rosati, Jonathan C. Runchey, Abhisek Sen, Alex Shaver, M. Shimomura, Arbin Timilsina, Shawn Douglas Whitaker, Et Al., Phenix Collaboration

Physics and Astronomy Publications

The cross section and transverse single-spin asymmetries of mu(-) and mu(+) from open heavy-flavor decays in polarized p + p collisions at root s = 200 GeV were measured by the PHENIX experiment during 2012 at the Relativistic Heavy Ion Collider. Because heavy-flavor production is dominated by gluon-gluon interactions at root s = 200 GeV, these measurements offer a unique opportunity to obtain information on the trigluon correlation functions. The measurements are performed at forward and backward rapidity (1.4 < vertical bar y vertical bar < 2.0) over the transverse momentum range of 1.25 < p(T) < 7 GeV/c for the cross section and 1.25 < p(T) < 5 GeV/c for the asymmetry measurements. The obtained cross section is compared to a fixed-order-plus-next-to-leading-log perturbative-quantum-chromodynamics calculation. The asymmetry results are consistent with zero within uncertainties, and a model calculation based on twist-3 three-gluon correlations agrees with the data.


Angular Decay Coefficients Of J/Psi Mesons At Forward Rapidity From P Plus P Collisions At Root S=510 Gev, Andrew Adare, Nicole Apadula, Sarah C. Campbell, Lei Ding, John C. Hill, Nels J. Hotvedt, Todd Kempel, John G. Lajoie, Alexandre Lebedev, Craig Ogilvie, Milap R. Patel, Joshua Perry, Timothy T. Rinn, Marzia Rosati, Jonathan C. Runchey, Abhisek Sen, M. Shimomura, Arbin Timilsina, Shawn Whitaker, Et Al., Phenix Collaboration May 2017

Angular Decay Coefficients Of J/Psi Mesons At Forward Rapidity From P Plus P Collisions At Root S=510 Gev, Andrew Adare, Nicole Apadula, Sarah C. Campbell, Lei Ding, John C. Hill, Nels J. Hotvedt, Todd Kempel, John G. Lajoie, Alexandre Lebedev, Craig Ogilvie, Milap R. Patel, Joshua Perry, Timothy T. Rinn, Marzia Rosati, Jonathan C. Runchey, Abhisek Sen, M. Shimomura, Arbin Timilsina, Shawn Whitaker, Et Al., Phenix Collaboration

Physics and Astronomy Publications

We report the first measurement of the full angular distribution for inclusive J/psi -> mu(+)mu(-) decays in p + p collisions at root s = 510 GeV. The measurements are made for J/psi transverse momentum 2 < p(T) < 10 GeV /c and rapidity 1.2 < y < 2.2 in the Helicity, Collins-Soper, and Gottfried-Jackson reference frames. In all frames the polar coefficient lambda theta is strongly negative at low p(T) and becomes close to zero at high p(T), while the azimuthal coefficient lambda phi is close to zero at low p(T), and becomes slightly negative at higher p(T). The frame-independent coefficient lambda is strongly negative at all p(T) in all frames. The data are compared to the theoretical predictions provided by nonrelativistic quantum chromodynamics models.


Measurements Of B -> J/Psi At Forward Rapidity In P Plus P Collisions At Root S=510 Gev, C. Aidala, Nicole Apadula, Sarah C. Campbell, Lei Ding, John C. Hill, Nels J. Hotvedt, John G. Lajoie, Alexandre Lebedev, Craig Ogilvie, Milap R. Patel, Joshua Perry, Timothy T. Rinn, Marzia Rosati, Jonathan C. Runchey, Abhisek Sen, Alex Shaver, M. Shimomura, Arbin Timilsina, Shawn Whitaker, Et Al., Phenix Collaboration May 2017

Measurements Of B -> J/Psi At Forward Rapidity In P Plus P Collisions At Root S=510 Gev, C. Aidala, Nicole Apadula, Sarah C. Campbell, Lei Ding, John C. Hill, Nels J. Hotvedt, John G. Lajoie, Alexandre Lebedev, Craig Ogilvie, Milap R. Patel, Joshua Perry, Timothy T. Rinn, Marzia Rosati, Jonathan C. Runchey, Abhisek Sen, Alex Shaver, M. Shimomura, Arbin Timilsina, Shawn Whitaker, Et Al., Phenix Collaboration

Physics and Astronomy Publications

We report the first measurement of the fraction of J/psi mesons coming from B-meson decay (F (B -> J/psi)) in p + p collisions at root s = 510 GeV. The measurement is performed using the forward silicon vertex detector and central vertex detector at PHENIX, which provide precise tracking and distance-of-closest-approach determinations, enabling the statistical separation of J=. due to B-meson decays from prompt J/psi. The measured value of F (B -> J/psi) is 8.1% +/- 2.3% (stat) +/- 1.9% (syst) for J/psi with transverse momenta 0 < p(T) < 5 GeV/c and rapidity 1.2 < vertical bar y vertical bar < 2.2. The measured fraction F (B -> J/psi) at PHENIX is compared to values measured by ...


Nonperturbative-Transverse-Momentum Effects And Evolution In Dihadron And Direct Photon-Hadron Angular Correlations In P Plus P Collisions At Root S=510 Gev, Andrew Adare, Nicole J. Apadula, Sarah C. Campbell, Lei Ding, John C. Hill, Nels J. Hotvedt, John G. Lajoie, Alexandre Lebedev, Craig Ogilvie, Milap R. Patel, Joshua Perry, Timothy T. Rinn, Marzia Rosati, Jonathan C. Runchey, Abhisek Sen, Alex Shaver, M. Shimomura, Arbin Timilsina, Shawn Whitaker, Et Al., Phenix Collaboration Apr 2017

Nonperturbative-Transverse-Momentum Effects And Evolution In Dihadron And Direct Photon-Hadron Angular Correlations In P Plus P Collisions At Root S=510 Gev, Andrew Adare, Nicole J. Apadula, Sarah C. Campbell, Lei Ding, John C. Hill, Nels J. Hotvedt, John G. Lajoie, Alexandre Lebedev, Craig Ogilvie, Milap R. Patel, Joshua Perry, Timothy T. Rinn, Marzia Rosati, Jonathan C. Runchey, Abhisek Sen, Alex Shaver, M. Shimomura, Arbin Timilsina, Shawn Whitaker, Et Al., Phenix Collaboration

Physics and Astronomy Publications

Dihadron and isolated direct photon-hadron angular correlations are measured in p + p collisions at root s = 510 GeV. Correlations of charged hadrons of 0.7 < p(T) < 10 GeV/c with pi(0) mesons of 4 < p(T) < 15 GeV/c or isolated direct photons of 7 < p(T) < 15 GeV/c are used to study nonperturbative effects generated by initial-state partonic transverse momentum and final-state transverse momentum from fragmentation. The nonperturbative behavior is characterized by measuring the out-of-plane transverse momentum component p(out) perpendicular to the axis of the trigger particle, which is the high-p(T) direct photon or pi(0). Nonperturbative evolution effects are extracted from Gaussian fits to the away-side inclusive-charged-hadron yields for different trigger-particle transverse momenta (p(T)(trig)). The Gaussian widths and root mean square of p(out) are reported as a function of the interaction hard scale p(T)(trig) to investigate possible transverse-momentum-dependent evolution differences between the pi(0)-h(+/-) and direct photon-h(+/-) correlations and factorization breaking effects. The widths are found to decrease with p(T)(trig) , which indicates that the Collins-Soper-Sterman soft factor is not driving the evolution with the hard scale in nearly back-to-back dihadron and direct photon-hadron production in p + p collisions. This behavior is in contrast to Drell-Yan and semi-inclusive deep-inelastic scattering measurements.


Measurements Of Double-Helicity Asymmetries In Inclusive J/Psi Production In Longitudinally Polarized P Plus P Collisions At Root S=510 Gev, Andrew Adare, Nicole Apadula, Lei Ding, John C. Hill, Nels J. Hotvedt, John G. Lajoie, Alexandre Lebedev, Craig Ogilvie, Milap R. Patel, Joshua Perry, Timothy T. Rinn, Marzia Rosati, Abhisek Sen, M. Shimomura, Arbin Timilsina, Shawn Whitaker, Et Al., Phenix Collaboration Dec 2016

Measurements Of Double-Helicity Asymmetries In Inclusive J/Psi Production In Longitudinally Polarized P Plus P Collisions At Root S=510 Gev, Andrew Adare, Nicole Apadula, Lei Ding, John C. Hill, Nels J. Hotvedt, John G. Lajoie, Alexandre Lebedev, Craig Ogilvie, Milap R. Patel, Joshua Perry, Timothy T. Rinn, Marzia Rosati, Abhisek Sen, M. Shimomura, Arbin Timilsina, Shawn Whitaker, Et Al., Phenix Collaboration

Physics and Astronomy Publications

We report the double-helicity asymmetry, A(LL)(J/Psi), in inclusive J/Psi production at forward rapidity as a function of transverse momentum p(T) and rapidity |y|. The data analyzed were taken during root s = 510 GeV longitudinally polarized p + p collisions at the Relativistic Heavy Ion Collider in the 2013 run using the PHENIX detector. At this collision energy, J/Psi particles are predominantly produced through gluon-gluon scatterings, thus A(LL)(J/Psi) is sensitive to the gluon polarization inside the proton. We measured A(LL)(J/Psi) by detecting the decay daughter muon pairs mu(+)mu(-) within ...


Centrality-Dependent Modification Of Jet-Production Rates In Deuteron-Gold Collisions At Root S(Nn)=200 Gev, Andrew Adare, Nicole Apadula, Sarah C. Campbell, Alan Dion, John C. Hill, Nels J. Hotvedt, Todd Kempel, John G. Lajoie, Alexandre Lebedev, Craig Ogilvie, Milap R. Patel, H. Pei, Joshua Perry, Timothy T. Rinn, Marzia Rosati, M. Shimomura, C. L. Silva, Arbin Timilsina, Feng Wei, Et Al., Phenix Collaboration Mar 2016

Centrality-Dependent Modification Of Jet-Production Rates In Deuteron-Gold Collisions At Root S(Nn)=200 Gev, Andrew Adare, Nicole Apadula, Sarah C. Campbell, Alan Dion, John C. Hill, Nels J. Hotvedt, Todd Kempel, John G. Lajoie, Alexandre Lebedev, Craig Ogilvie, Milap R. Patel, H. Pei, Joshua Perry, Timothy T. Rinn, Marzia Rosati, M. Shimomura, C. L. Silva, Arbin Timilsina, Feng Wei, Et Al., Phenix Collaboration

Physics and Astronomy Publications

Jet production rates are measured in p + p and d + Au collisions at root s(NN) = 200 GeV recorded in 2008 with the PHENIX detector at the Relativistic Heavy Ion Collider. Jets are reconstructed using the R = 0.3 anti-k(t) algorithm from energy deposits in the electromagnetic calorimeter and charged tracks in multiwire proportional chambers, and the jet transverse momentum (p(T)) spectra are corrected for the detector response. Spectra are reported for jets with 12 < p(T) < 50 GeV/c, within a pseudorapidity acceptance of vertical bar eta vertical bar < 0.3. The nuclear-modification factor (R-dAu) values for 0%-100% d + Au events are found to be consistent with unity, constraining the role of initial state effects on jet production. However, the centrality-selected RdAu values and central-to-peripheral ratios (R-CP) show large, p(T)-dependent deviations from unity, challenging the conventional models that relate hard-process rates and soft-particle production in collisions involving nuclei.


Measurement Of Parity-Violating Spin Asymmetries In W-+/- Production At Midrapidity In Longitudinally Polarized P Plus P Collisions, Andrew Adare, Nicole Apadula, Sarah C. Campbell, Lei Ding, Alan Dion, John C. Hill, Nels J. Hotvedt, Todd Kempel, John G. Lajoie, Alexandre Lebedev, Craig Ogilvie, Milap R. Patel, H. Pei, Joshua Perry, Timothy T. Rinn, Marzia Rosati, Alex Shaver, M. Shimomura, Arbin Timilsina, Brian K. Voas, Shawn Whitaker, Et Al., Phenix Collaboration Mar 2016

Measurement Of Parity-Violating Spin Asymmetries In W-+/- Production At Midrapidity In Longitudinally Polarized P Plus P Collisions, Andrew Adare, Nicole Apadula, Sarah C. Campbell, Lei Ding, Alan Dion, John C. Hill, Nels J. Hotvedt, Todd Kempel, John G. Lajoie, Alexandre Lebedev, Craig Ogilvie, Milap R. Patel, H. Pei, Joshua Perry, Timothy T. Rinn, Marzia Rosati, Alex Shaver, M. Shimomura, Arbin Timilsina, Brian K. Voas, Shawn Whitaker, Et Al., Phenix Collaboration

Physics and Astronomy Publications

We present midrapidity measurements from the PHENIX experiment of large parity-violating single-spin asymmetries of high transverse momentum electrons and positrons from W-+/-/Z decays, produced in longitudinally polarized p + p collisions at center of mass energies of root s = 500 and 510 GeV. These asymmetries allow direct access to the antiquark polarized parton distribution functions due to the parity-violating nature of the W-boson coupling to quarks and antiquarks. The results presented are based on data collected in 2011, 2012, and 2013 with an integrated luminosity of 240 pb(-1), which exceeds previous PHENIX published results by a factor of more ...


Measurements Of Elliptic And Triangular Flow In High-Multiplicity He-3 + Au Collisions At Root S(Nn)=200 Gev, Andrew Adare, Nicole Apadula, Sarah C. Campbell, Alan Dion, Nathan C. Grau, John C. Hill, Nels J. Hotvedt, Todd Kempel, John G. Lajoie, Alexandre Lebedev, Craig Ogilvie, Milap R. Patel, H. Pei, Joshua Perry, Timothy T. Rinn, Marzia Rosati, Alexey Yu. Semenov, M. Shimomura, C. L. Silva, S. Skutnik, Arbin Timilsina, Carla Vale, Feng Wei, Et Al., Phenix Collaboration Sep 2015

Measurements Of Elliptic And Triangular Flow In High-Multiplicity He-3 + Au Collisions At Root S(Nn)=200 Gev, Andrew Adare, Nicole Apadula, Sarah C. Campbell, Alan Dion, Nathan C. Grau, John C. Hill, Nels J. Hotvedt, Todd Kempel, John G. Lajoie, Alexandre Lebedev, Craig Ogilvie, Milap R. Patel, H. Pei, Joshua Perry, Timothy T. Rinn, Marzia Rosati, Alexey Yu. Semenov, M. Shimomura, C. L. Silva, S. Skutnik, Arbin Timilsina, Carla Vale, Feng Wei, Et Al., Phenix Collaboration

Physics and Astronomy Publications

We present the first measurement of elliptic (v(2)) and triangular (v(3)) flow in high-multiplicity He-3 + Au collisions at root s(NN) = 200 GeV. Two-particle correlations, where the particles have a large separation in pseudorapidity, are compared in He-3 + Au and in p + p collisions and indicate that collective effects dominate the second and third Fourier components for the correlations observed in the He-3 + Au system. The collective behavior is quantified in terms of elliptic v(2) and triangular v(3) anisotropy coefficients measured with respect to their corresponding event planes. The v(2) values are comparable to those ...


Measurement Of Long-Range Angular Correlation And Quadrupole Anisotropy Of Pions And (Anti) Protons In Central D Plus Au Collisions At Root S(Nn)=200 Gev, Andrew Adare, Alan Dion, John C. Hill, Todd Kempel, John G. Lajoie, Alexandre Lebedev, Craig Ogilvie, H. Pei, Marzia Rosati, C. L. Silva, Feng Wei, Et Al., Phenix Collaboration May 2015

Measurement Of Long-Range Angular Correlation And Quadrupole Anisotropy Of Pions And (Anti) Protons In Central D Plus Au Collisions At Root S(Nn)=200 Gev, Andrew Adare, Alan Dion, John C. Hill, Todd Kempel, John G. Lajoie, Alexandre Lebedev, Craig Ogilvie, H. Pei, Marzia Rosati, C. L. Silva, Feng Wei, Et Al., Phenix Collaboration

Physics and Astronomy Publications

We present azimuthal angular correlations between charged hadrons and energy deposited in calorimeter towers in central d + Au and minimum bias p + p collisions at root s(NN) = 200 GeV. The charged hadron is measured at midrapidity vertical bar eta vertical bar < 0.35, and the energy is measured at large rapidity (-3.7 < eta < -3.1, Au-going direction). An enhanced near-side angular correlation across vertical bar Delta eta vertical bar > 2.75 is observed in d + Au collisions. Using the event plane method applied to the Au-going energy distribution, we extract the anisotropy strength v(2) for inclusive charged hadrons at midrapidity up to p(T) = 4.5 GeV/c. We also present the measurement of v(2) for identified pi(+/-) and (anti)protons in central d + Au ...


Charged-Pion Cross Sections And Double-Helicity Asymmetries In Polarized P Plus P Collisions At Root S=200 Gev, Andrew Adare, Alan Dion, John C. Hill, Todd Kempel, John G. Lajoie, Alexandre Lebedev, Craig Ogilvie, H. Pei, Marzia Rosati, C. L. Silva, Feng Wei, Et Al., Phenix Collaboration Feb 2015

Charged-Pion Cross Sections And Double-Helicity Asymmetries In Polarized P Plus P Collisions At Root S=200 Gev, Andrew Adare, Alan Dion, John C. Hill, Todd Kempel, John G. Lajoie, Alexandre Lebedev, Craig Ogilvie, H. Pei, Marzia Rosati, C. L. Silva, Feng Wei, Et Al., Phenix Collaboration

Physics and Astronomy Publications

We present midrapidity charged-pion invariant cross sections, the ratio of the pi(-) to pi(+) cross sections and the charge-separated double-spin asymmetries in polarized p + p collisions at root s = p + 200 GeV. While the cross section measurements are consistent within the errors of next-to-leading-order (NLO) perturbative quantum chromodynamics predictions (pQCD), the same calculations overestimate the ratio of the charged-pion cross sections. This discrepancy arises from the cancellation of the substantial systematic errors associated with the NLO-pQCD predictions in the ratio and highlights the constraints these data will place on flavor-dependent pion fragmentation functions. The charge-separated pion asymmetries presented here sample ...


Cross Section And Transverse Single-Spin Asymmetry Of Eta Mesons In P Up Arrow Plus P Collisions At Root S=200 Gev At Forward Rapidity, Andrew Adare, Nicole Apadula, Sarah C. Campbell, Lei Ding, Alan Dion, John C. Hill, Todd Kempel, John G. Lajoie, Alexandre Lebedev, Craig Ogilvie, Milap R. Patel, H. Pei, Joshua Perry, Marzia Rosati, M. Shimomura, C. L. Silva, Arbin Timilsina, Fang Wei, Shawn Whitaker, Et Al., Phenix Collaboration Oct 2014

Cross Section And Transverse Single-Spin Asymmetry Of Eta Mesons In P Up Arrow Plus P Collisions At Root S=200 Gev At Forward Rapidity, Andrew Adare, Nicole Apadula, Sarah C. Campbell, Lei Ding, Alan Dion, John C. Hill, Todd Kempel, John G. Lajoie, Alexandre Lebedev, Craig Ogilvie, Milap R. Patel, H. Pei, Joshua Perry, Marzia Rosati, M. Shimomura, C. L. Silva, Arbin Timilsina, Fang Wei, Shawn Whitaker, Et Al., Phenix Collaboration

Physics and Astronomy Publications

We present a measurement of the cross section and transverse single-spin asymmetry (AN) for. mesons at large pseudorapidity from root s = 200 GeV p up arrow + p collisions. The measured cross section for 0.5 < p(T) < 5.0 GeV/c and 3.0 < vertical bar eta vertical bar < 3.8 is well described by a next-to-leading-order perturbative-quantum-chromodynamics calculation. The asymmetries A(N) have been measured as a function of Feynman-x (x(F)) from 0.2 < vertical bar x(F)vertical bar < 0.7, as well as transverse momentum (p(T)) from 1.0 < p(T) < 4.5 GeV/c. The asymmetry averaged over positive x(F) is < A(N)> = 0.061 +/- 0.014. The results are consistent with prior transverse single-spin measurements of forward eta and pi(0) mesons at various energies in overlapping x(F) ranges. Comparison of different particle species can help to determine the origin of the large observed asymmetries in p up arrow + p collisions.


Low-Mass Vector-Meson Production At Forward Rapidity In P Plus P Collisions At Root S=200 Gev, Andrew Adare, Nicole Apadula, Sarah C. Campbell, Lei Ding, Alan Dion, John C. Hill, Todd Kempel, John G. Lajoie, Alexandre Lebedev, Craig Ogilvie, Milap R. Patel, H. Pei, Joshua Perry, Marzia Rosati, M. Shimomura, C. L. Silva, Arbin Timilsina, Feng Wei, Shawn Whitaker, Et Al., Phenix Collaboration Sep 2014

Low-Mass Vector-Meson Production At Forward Rapidity In P Plus P Collisions At Root S=200 Gev, Andrew Adare, Nicole Apadula, Sarah C. Campbell, Lei Ding, Alan Dion, John C. Hill, Todd Kempel, John G. Lajoie, Alexandre Lebedev, Craig Ogilvie, Milap R. Patel, H. Pei, Joshua Perry, Marzia Rosati, M. Shimomura, C. L. Silva, Arbin Timilsina, Feng Wei, Shawn Whitaker, Et Al., Phenix Collaboration

Physics and Astronomy Publications

The PHENIX experiment at the Relativistic Heavy Ion Collider has measured low-mass vector-meson, omega, rho, and phi, production through the dimuon decay channel at forward rapidity (1.2 < vertical bar y vertical bar < 2.2) in p + p collisions at root s = 200 GeV. The differential cross sections for these mesons are measured as a function of both p(T) and rapidity. We also report the integrated differential cross sections over 1 < p(T) < 7 GeV/c and 1.2 < vertical bar y vertical bar < 2.2: d sigma/dy(omega + rho rho -> mu mu) = 80 +/- 6(stat) +/- 12(syst)nb and d sigma/dy(phi -> mu mu) = 27 +/- 3(stat) +/- 4(syst)nb. These results are compared with midrapidity measurements and calculations.


Inclusive Double-Helicity Asymmetries In Neutral-Pion And Eta-Meson Production In <(P) Over Right Arrow> + <(P) Over Right Arrow> Collisions At Root S=200 Gev, Andrew Adare, Alan Dion, John C. Hill, Todd Kempel, John G. Lajoie, Alexandre Lebedev, Craig Ogilvie, H. Pei, Marzia Rosati, C. L. Silva, Feng Wei, Et Al., Phenix Collaboration Jul 2014

Inclusive Double-Helicity Asymmetries In Neutral-Pion And Eta-Meson Production In + Collisions At Root S=200 Gev, Andrew Adare, Alan Dion, John C. Hill, Todd Kempel, John G. Lajoie, Alexandre Lebedev, Craig Ogilvie, H. Pei, Marzia Rosati, C. L. Silva, Feng Wei, Et Al., Phenix Collaboration

Physics and Astronomy Publications

Results are presented from data recorded in 2009 by the PHENIX experiment at the Relativistic Heavy Ion Collider for the double-longitudinal spin asymmetry, A(LL), for pi(0) and eta production in root s = 200 GeV polarized p + p collisions. Comparison of the pi(0) results with different theory expectations based on fits of other published data showed a preference for small positive values of gluon polarization, Delta G, in the proton in the probed Bjorken x range. The effect of adding the new 2009 pi(0) data to a recent global analysis of polarized scattering data is also shown ...


Measurement Of Transverse-Single-Spin Asymmetries For Midrapidity And Forward-Rapidity Production Of Hadrons In Polarized P Plus P Collisions At Root S=200 And 62.4 Gev, Andrew Adare, Alan Dion, John C. Hill, Todd Kempel, John G. Lajoie, Alexandre Lebedev, Craig Ogilvie, H. Pei, Marzia Rosati, Alexey Yu. Semenov, C. L. Silva, Carla Vale, Feng Wei, Et Al., Phenix Collaboration Jul 2014

Measurement Of Transverse-Single-Spin Asymmetries For Midrapidity And Forward-Rapidity Production Of Hadrons In Polarized P Plus P Collisions At Root S=200 And 62.4 Gev, Andrew Adare, Alan Dion, John C. Hill, Todd Kempel, John G. Lajoie, Alexandre Lebedev, Craig Ogilvie, H. Pei, Marzia Rosati, Alexey Yu. Semenov, C. L. Silva, Carla Vale, Feng Wei, Et Al., Phenix Collaboration

Physics and Astronomy Publications

Measurements of transverse-single-spin asymmetries (A(N)) in p + p collisions at root s = 62.4 and 200 GeV with the PHENIX detector at the Relativistic Heavy Ion Collider are presented. At midrapidity, A(N) is measured for neutral pion and eta mesons reconstructed from diphoton decay, and, at forward rapidities, neutral pions are measured using both diphotons and electromagnetic clusters. The neutral-pion measurement of A(N) at midrapidity is consistent with zero with uncertainties a factor of 20 smaller than previous publications, which will lead to improved constraints on the gluon Sivers function. At higher rapidities, where the valence quark ...


Cold-Nuclear-Matter Effects On Heavy-Quark Production At Forward And Backward Rapidity In D + Au Collisions At Root S(Nn) = Gev, Andrew Adare, Alan Dion, John C. Hill, Todd Kempel, John G. Lajoie, Alexandre Lebedev, Craig Ogilvie, H. Pei, Marzia Rosati, C. L. Silva, Feng Wei, Et Al., Phenix Collaboration Jun 2014

Cold-Nuclear-Matter Effects On Heavy-Quark Production At Forward And Backward Rapidity In D + Au Collisions At Root S(Nn) = Gev, Andrew Adare, Alan Dion, John C. Hill, Todd Kempel, John G. Lajoie, Alexandre Lebedev, Craig Ogilvie, H. Pei, Marzia Rosati, C. L. Silva, Feng Wei, Et Al., Phenix Collaboration

Physics and Astronomy Publications

The PHENIX experiment has measured open heavy-flavor production via semileptonic decay over the transverse momentum range 1 < p(T) < 6 GeV/c at forward and backward rapidity (1.4 < vertical bar y vertical bar < 2.0) in d + Au and p + p collisions at root s(NN) = 200 GeV. In central d + Au collisions, relative to the yield in p + p collisions scaled by the number of binary nucleon-nucleon collisions, a suppression is observed at forward rapidity (in the d-going direction) and an enhancement at backward rapidity (in the Au-going direction). Predictions using nuclear-modified-parton-distribution functions, even with additional nuclear-p(T) broadening, cannot simultaneously reproduce the data at both rapidity ranges, which implies that these models are incomplete and suggests the possible importance of final-state interactions in the asymmetric d + Au collision system. These results can be used to probe cold-nuclear-matter effects, which may significantly affect heavy-quark production, in addition to helping constrain the magnitude of charmonia-breakup effects in nuclear matter.


Azimuthal-Angle Dependence Of Charged-Pion-Interferometry Measurements With Respect To Second- And Third-Order Event Planes In Au Plus Au Collisions At Root S-Nn=200 Gev, Andrew Adare, John C. Hill, Todd Kempel, John G. Lajoie, Alexandre Lebedev, Craig Ogilvie, H. Pei, Marzia Rosati, Alexey Yu. Semenov, Carla Vale, Feng Wei, Et Al., Phenix Collaboration Jun 2014

Azimuthal-Angle Dependence Of Charged-Pion-Interferometry Measurements With Respect To Second- And Third-Order Event Planes In Au Plus Au Collisions At Root S-Nn=200 Gev, Andrew Adare, John C. Hill, Todd Kempel, John G. Lajoie, Alexandre Lebedev, Craig Ogilvie, H. Pei, Marzia Rosati, Alexey Yu. Semenov, Carla Vale, Feng Wei, Et Al., Phenix Collaboration

Physics and Astronomy Publications

Charged-pion-interferometry measurements were made with respect to the second-and third-order event plane for Au + Au collisions at root S-NN = 200 GeV. A strong azimuthal-angle dependence of the extracted Gaussian-source radii was observed with respect to both the second-and third-order event planes. The results for the second-order dependence indicate that the initial eccentricity is reduced during the medium evolution, which is consistent with previous results. In contrast, the results for the third-order dependence indicate that the initial triangular shape is significantly reduced and potentially reversed by the end of the medium evolution, and that the third-order oscillations are largely dominated by ...


Quadrupole Anisotropy In Dihadron Azimuthal Correlations In Central D Plus Au Collisions At Root S(Nn)=200 Gev, Andrew Adare, John C. Hill, Todd Kempel, John G. Lajoie, Alexandre Lebedev, Craig Ogilvie, H. Pei, Marzia Rosati, C. L. Silva, Feng Wei, Et Al., Phenix Collaboration Nov 2013

Quadrupole Anisotropy In Dihadron Azimuthal Correlations In Central D Plus Au Collisions At Root S(Nn)=200 Gev, Andrew Adare, John C. Hill, Todd Kempel, John G. Lajoie, Alexandre Lebedev, Craig Ogilvie, H. Pei, Marzia Rosati, C. L. Silva, Feng Wei, Et Al., Phenix Collaboration

Physics and Astronomy Publications

The PHENIX collaboration at the Relativistic Heavy Ion Collider (RHIC) reports measurements of azimuthal dihadron correlations near midrapidity in d + Au collisions at root s(NN) = 200 GeV. These measurements complement recent analyses by experiments at the Large Hadron Collider (LHC) involving central p + Pb collisions at root s(NN) = 5.02 TeV, which have indicated strong anisotropic long-range correlations in angular distributions of hadron pairs. The origin of these anisotropies is currently unknown. Various competing explanations include parton saturation and hydrodynamic flow. We observe qualitatively similar, but larger, anisotropies in d + Au collisions at RHIC compared to those seen ...


Nuclear Modification Of Psi ', Chi(C), And J/Psi Production In D Plus Au Collisions At Root S(Nn)=200 Gev, Andrew Adare, Alan Dion, John C. Hill, Todd Kempel, John G. Lajoie, Alexandre Lebedev, Craig Ogilvie, H. Pei, Marzia Rosati, C. L. Silva, Feng Wei, Et Al., Phenix Collaboration Nov 2013

Nuclear Modification Of Psi ', Chi(C), And J/Psi Production In D Plus Au Collisions At Root S(Nn)=200 Gev, Andrew Adare, Alan Dion, John C. Hill, Todd Kempel, John G. Lajoie, Alexandre Lebedev, Craig Ogilvie, H. Pei, Marzia Rosati, C. L. Silva, Feng Wei, Et Al., Phenix Collaboration

Physics and Astronomy Publications

We present results for three charmonia states (psi' chi(c), and J/ psi) in d + Au collisions at vertical bar y vertical bar < 0.35 and root s(NN) = 200 GeV. We find that the modification of the psi' yield relative to that of the J/ psi scales approximately with charged particle multiplicity at midrapidity across p + A, d + Au, and A + A results from the Super Proton Synchrotron and the Relativistic Heavy Ion Collider. In large-impact-parameter collisions we observe a similar suppression for the psi' and J/ psi, while in small-impact-parameter collisions the more weakly bound psi' is more strongly suppressed. Owing to the short time spent traversing the Au nucleus, the larger psi' suppression in central events is not explained by an increase of the nuclear absorption owing to meson formation time effects.


Spectra And Ratios Of Identified Particles In Au Plus Au And D Plus Au Collisions At Root S(Nn)=200 Gev, Andrew Adare, Alan Dion, John C. Hill, Todd Kempel, John G. Lajoie, Alexandre Lebedev, Craig Ogilvie, H. Pei, Marzia Rosati, Alexey Yu. Semenov, C. L. Silva, Carla Vale, Feng Wei, Et Al., Phenix Collaboration Aug 2013

Spectra And Ratios Of Identified Particles In Au Plus Au And D Plus Au Collisions At Root S(Nn)=200 Gev, Andrew Adare, Alan Dion, John C. Hill, Todd Kempel, John G. Lajoie, Alexandre Lebedev, Craig Ogilvie, H. Pei, Marzia Rosati, Alexey Yu. Semenov, C. L. Silva, Carla Vale, Feng Wei, Et Al., Phenix Collaboration

Physics and Astronomy Publications

The transverse momentum (p(T)) spectra and ratios of identified charged hadrons (pi(+/-), K-+/-, p, (p) over bar) produced in root s(NN) = 200 GeV Au + Au and d + Au collisions are reported in five different centrality classes for each collision species. The measurements of pions and protons are reported up to p(T) = 6 GeV/c (5 GeV/c), and the measurements of kaons are reported up to p(T) = 4 GeV/c (3.5 GeV/c) in Au + Au (d + Au) collisions. In the intermediate p(T) region, between 2 and 5 GeV/c, a significant enhancement of ...


Inclusive Cross Section And Single Transverse Spin Asymmetry For Very Forward Neutron Production In Polarized P Plus P Collisions At Root S=200 Gev, Andrew Adare, John C. Hill, Todd Kempel, John G. Lajoie, Alexandre Lebedev, Craig Ogilvie, H. Pei, Marzia Rosati, Alexey Yu. Semenov, Carla Vale, Feng Wei, Et Al., Phenix Collaboration Aug 2013

Inclusive Cross Section And Single Transverse Spin Asymmetry For Very Forward Neutron Production In Polarized P Plus P Collisions At Root S=200 Gev, Andrew Adare, John C. Hill, Todd Kempel, John G. Lajoie, Alexandre Lebedev, Craig Ogilvie, H. Pei, Marzia Rosati, Alexey Yu. Semenov, Carla Vale, Feng Wei, Et Al., Phenix Collaboration

Physics and Astronomy Publications

The energy dependence of the single-transverse-spin asymmetry, A(N), and the cross section for neutron production at very forward angles were measured in the PHENIX experiment at the Relativistic Heavy Ion Collider for polarized p + p collisions at root s = 200 GeV. The neutrons were observed in forward detectors covering an angular range of up to 2.2 mrad. We report results for neutrons with a momentum fraction of x(F) = 0.45 to 1.0. The energy dependence of the measured cross sections were consistent with x(F) scaling, compared to measurements by an experiment at the Intersecting Storage ...