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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).


Discontinuous Phase Transitions In Nonlocal Schloegl Models For Autocatalysis: Loss And Reemergence Of A Nonequilibrium Gibbs Phase Rule, Da-Jiang Liu, Chi-Jen Wang, James W. Evans Sep 2018

Discontinuous Phase Transitions In Nonlocal Schloegl Models For Autocatalysis: Loss And Reemergence Of A Nonequilibrium Gibbs Phase Rule, Da-Jiang Liu, Chi-Jen Wang, James W. Evans

Ames Laboratory Accepted Manuscripts

We consider Schloegl models (or contact processes) where particles on a square grid annihilate at a rate p and are created at a rate of kn=n(n−1)/[N(N−1)] at empty sites with n particles in a neighborhood ΩN of size N. Simulation reveals a discontinuous transition between populated and vacuum states, but equistable p=peq determined by the stationarity of planar interfaces between these states depends on the interface orientation and on ΩN. The behavior for large ΩN follows from continuum equations. These also depend on the interface orientation and on ΩN shape, but a unique ...


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


Constraints On Neutrino Oscillation Parameters With The Nova Experiment, Erika Cantano-Mur Jan 2018

Constraints On Neutrino Oscillation Parameters With The Nova Experiment, Erika Cantano-Mur

Graduate Theses and Dissertations

NOvA is a long-baseline neutrino oscillation experiment, which consists of two finely-segmented liquid-scintillator detectors

operating 14 mrad off-axis from the NuMI muon neutrino beam. With an 810 km baseline, the combined measurements of muon neutrino disappearance and electron neutrino appearance allow the determination of neutrino oscillation unknowns, namely the mass hierarchy, the octant of the largest neutrino mixing angle, and the CP violating phase.

In this dissertation, I present the joint analysis of $\nu_\mu\to\nu_\mu$ and $\nu_mu\to\nu_e$ oscillation data with an exposure of

$8.85\times10^{20}$ protons on target on the 14 kton detector ...


Electronic, Magnetic, And Magnetocrystalline Anisotropy Properties Of Light Lanthanides, T. A. Hackett, D. J. Baldwin, Durga Paudyal Nov 2017

Electronic, Magnetic, And Magnetocrystalline Anisotropy Properties Of Light Lanthanides, T. A. Hackett, D. J. Baldwin, Durga Paudyal

Ames Laboratory Accepted Manuscripts

Theoretical understanding of interactions between localized and mobile electrons and the crystal environment in light lanthanides is important because of their key role in much needed magnetic anisotropy in permanent magnet materials that have a great impact in automobile and wind turbine applications. We report electronic, magnetic, and magnetocrystalline properties of these basic light lanthanide elements studied from advanced density functional theory (DFT) calculations. We find that the inclusion of onsite 4f electron correlation and spin orbit coupling within the full-potential band structure is needed to understand the unique magnetocrystalline properties of these light lanthanides. The onsite electron correlation, spin ...


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.


The Extension Of Two-Higgs-Doublet Model With A Color-Octet Scalar, Li Cheng Jan 2017

The Extension Of Two-Higgs-Doublet Model With A Color-Octet Scalar, Li Cheng

Graduate Theses and Dissertations

In this thesis, we develop a model that extends scalar sector of Two-Higgs-Doublet Model by adding a color-octet scalar.

Firstly, we construct the scalar potential with the color-octet scalar. The potential consists of three parts. The first part is the Two-Higgs-Doublet Model potential which describe the self interactions of the two Higgs doublets. The second part is the self interactions of the color-octet scalar. The third part arises from the interplay between the color-octet scalar and two Higgs doublets.

To comply with the experimental facts that strength of flavor changing neutral currents are strongly limited, we apply the principle of ...


Oscillatory Electrostatic Potential On Graphene Induced By Group Iv Element Decoration, Chunyan Du, Liwei Yu, Xiaojie Liu, Lili Liu, Cai-Zhuang Wang Jan 2017

Oscillatory Electrostatic Potential On Graphene Induced By Group Iv Element Decoration, Chunyan Du, Liwei Yu, Xiaojie Liu, Lili Liu, Cai-Zhuang Wang

Ames Laboratory Accepted Manuscripts

The structures and electronic properties of partial C, Si and Ge decorated graphene were investigated by first-principles calculations. The calculations show that the interaction between graphene and the decoration patches is weak and the semiconductor patches act as agents for weak electron doping without much disturbing graphene electronic π-bands. Redistribution of electrons due to the partial decoration causes the electrostatic potential lower in the decorated graphene areas, thus induced an electric field across the boundary between the decorated and non-decorated domains. Such an alternating electric field can change normal stochastic adatom diffusion to biased diffusion, leading to selective mass transport.


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 ...


Analysis Of Gas-Solid Flow Using Particle-Resolved Direct Numerical Simulation: Flow Physics And Modeling, Mohammad Mehrabadi Jan 2016

Analysis Of Gas-Solid Flow Using Particle-Resolved Direct Numerical Simulation: Flow Physics And Modeling, Mohammad Mehrabadi

Graduate Theses and Dissertations

Gas-solid flows are encountered in many industrial processes such as pneumatic conveying, fluid catalytic cracking, CO2 capture and fast pyrolysis process. In spite of several experimental and numerical studies performed to understand the physics governing observed phenomena in gas-solid flows, and to propose accurate closure models for computational fluid dynamics (CFD) simulations using the averaged conservation equations, there are several challenges in gas-solid flows that yet need to be addressed. In many of the industrial processes, the solid-to-fluid density ratio is of the order of 100 to 1000, and the particle diameter ranges from 50 to 500 micron. The interaction ...


A Study Of The Performance Of The Topological Clustering And Anti-Kt Algorithms Using Graphical Processing Units, Matthew Joseph Lockner Jan 2016

A Study Of The Performance Of The Topological Clustering And Anti-Kt Algorithms Using Graphical Processing Units, Matthew Joseph Lockner

Graduate Theses and Dissertations

The advent and proliferation of modern graphical processing units (GPUs) containing hundreds to thousands of cores opens up the new possibility of rewriting programs to execute on GPUs and acheive significant gains in speed over the original implementation. We examine two algorithms taken from high-energy physics: topological clustering, and the anti-k_{T} jet finding algorithm. While no performance gains were attained for topological clustering, the execution time of the anti-k_{T} algorithm is nearly halved.


Observing Muon Neutrino To Electron Neutrino Oscillations In The Nova Experiment, Tian Xin Jan 2016

Observing Muon Neutrino To Electron Neutrino Oscillations In The Nova Experiment, Tian Xin

Graduate Theses and Dissertations

Neutrino oscillations offers an insight on new physics beyond the Standard Model. The three mixing angles ($\theta_{12}$, $\theta_{13}$ and $\theta_{23}$) and the two mass splittings ($\Delta m^2_{12}$ and $\Delta m^2_{23}$) have been measured by different neutrino oscillation experiments. Some other parameters including the mass ordering of different neutrino mass eigenstates and the CP violation phase are still unknown.

\nova~is a long-baseline accelerator neutrino experiment, using neutrinos from the NuMI beam at Fermilab. The experiment is equipped with two functionally identical detectors about 810 kilometers apart and 14 mrad off the beam axis ...


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.