Open Access. Powered by Scholars. Published by Universities.®
- Keyword
-
- STAR (3)
- Collisions (2)
- System (2)
- A-dependence (1)
- Anisotrophy (1)
-
- Asymmetry (1)
- Au + Au (1)
- Au + Au collisions (1)
- Axizl form factor (1)
- Baryon states (1)
- Bose-Einstein correlations (1)
- By-event fluctuations (1)
- CLAS (1)
- Charged particles (1)
- Collaboration (1)
- Conservation (1)
- Cr (1)
- Crabbing cavities (1)
- Cross section (1)
- Cross sections (1)
- Cross sections of exclusive electroproduction (1)
- Design parameters (1)
- Elastic scattering (1)
- Energy (1)
- Excitation energy gap (1)
- Fe (1)
- Fermi surface (1)
- Fusion-evaporation reactions (1)
- Gamma ray energy coincidence analyses (1)
- Generalized form factor (1)
Articles 1 - 17 of 17
Full-Text Articles in Physics
Remnants Of Spherical Shell Structures In Deformed Nuclei: The Impact Of An N = 64 Neutron Subshell Closure On The Structure Of N ≈ 90 Gadolinium Nuclei, T. J. Ross, R. O. Hughes, C. W. Beausang, J. M. Allmond, C. Angell, M. S. Basunia, D. L. Bleuel, J. T. Burke, R. J. Casperson, J. Escher, P. Fallon, R. Hatarik, J. Munson, S. Paschalis, M. Petri, L. Phair, J. J. Ressler, N. D. Scielzo
Remnants Of Spherical Shell Structures In Deformed Nuclei: The Impact Of An N = 64 Neutron Subshell Closure On The Structure Of N ≈ 90 Gadolinium Nuclei, T. J. Ross, R. O. Hughes, C. W. Beausang, J. M. Allmond, C. Angell, M. S. Basunia, D. L. Bleuel, J. T. Burke, R. J. Casperson, J. Escher, P. Fallon, R. Hatarik, J. Munson, S. Paschalis, M. Petri, L. Phair, J. J. Ressler, N. D. Scielzo
Physics Faculty Publications
Odd-mass gadolinium isotopes around N = 90 were populated by the (p,d) reaction, utilizing 25-MeV protons, resulting in population of low-spin quasineutron states at energies near and below the Fermi surface. Systematics of the single quasineutron levels populated are presented. A large excitation energy gap is observed between levels originating from the 2d3/2, 1h11/2, and 3s1/2 spherical parents (above the N = 64 gap), and the 2d5/2 (below the gap), indicating that the spherical shell model level spacing is maintained at least to moderate deformations.
Freeze-Out Dynamics Via Charged Kaon Femtoscopy In √ S N N = 200 Gev Central Au + Au Collisions, L. Adamczyk, J. K. Adkins, G. Agakishiev, M. M. Aggarwal, Z. Ahammed, I. Alekseev, S. Bültmann, I. Koralt, D. Plyku, Star Collaboration
Freeze-Out Dynamics Via Charged Kaon Femtoscopy In √ S N N = 200 Gev Central Au + Au Collisions, L. Adamczyk, J. K. Adkins, G. Agakishiev, M. M. Aggarwal, Z. Ahammed, I. Alekseev, S. Bültmann, I. Koralt, D. Plyku, Star Collaboration
Physics Faculty Publications
We present measurements of three-dimensional correlation functions of like-sign, low-transverse-momentum kaon pairs from √sNN=200 GeV Au+Au collisions. A Cartesian surface-spherical harmonic decomposition technique was used to extract the kaon source function. The latter was found to have a three-dimensional Gaussian shape and can be adequately reproduced by Therminator event-generator simulations with resonance contributions taken into account. Compared to the pion one, the kaon source function is generally narrower and does not have the long tail along the pair transverse momentum direction. The kaon Gaussian radii display a monotonic decrease with increasing transverse mass mT over the interval of 0.55≤mT …
Third Harmonic Flow Of Charged Particles In Au + Au Collisions At √ S Nn = 200 Gev, L. Adamczyk, J. K. Adkins, G. Agakishiev, M. M. Aggarwal, Z. Ahammed, Av. V. Alakhverdyants, I. Alekseev, S. Bültmann, I. Koraly, Star Collaboration
Third Harmonic Flow Of Charged Particles In Au + Au Collisions At √ S Nn = 200 Gev, L. Adamczyk, J. K. Adkins, G. Agakishiev, M. M. Aggarwal, Z. Ahammed, Av. V. Alakhverdyants, I. Alekseev, S. Bültmann, I. Koraly, Star Collaboration
Physics Faculty Publications
We report measurements of the third harmonic coefficient of the azimuthal anisotropy, v3, known as triangular flow. The analysis is for charged particles in Au+Au collisions at √sNN=200 GeV, based on data from the STAR experiment at the BNL Relativistic Heavy Ion Collider. Two-particle correlations as a function of their pseudorapidity separation are fit with narrow and wide Gaussians. Measurements of triangular flow are extracted from the wide Gaussian, from two-particle cumulants with a pseudorapidity gap, and also from event plane analysis methods with a large pseudorapidity gap between the particles and the event plane. These results are …
Quadrupole Collectivity In Neutron-Rich Fe And Cr Isotopes, H. L. Crawford, R. M. Clark, P. Fallon, A. O. Macchiavelli, T. Baugher, D. Bazin, C. W. Beausang, J. S. Berryman, D. L. Bleuel, C. M. Campbell, M. Cromaz, G. De Angelis, A. Gade, R. O. Hughes, I. Y. Lee, S. M. Lenzi, F. Nowacki, S. Paschalis, M. Petri, A. Poves, A. Ratkiewicz, T. J. Ross, E. Sahin, D. Weisshaar, K. Wimmer, R. Winkler
Quadrupole Collectivity In Neutron-Rich Fe And Cr Isotopes, H. L. Crawford, R. M. Clark, P. Fallon, A. O. Macchiavelli, T. Baugher, D. Bazin, C. W. Beausang, J. S. Berryman, D. L. Bleuel, C. M. Campbell, M. Cromaz, G. De Angelis, A. Gade, R. O. Hughes, I. Y. Lee, S. M. Lenzi, F. Nowacki, S. Paschalis, M. Petri, A. Poves, A. Ratkiewicz, T. J. Ross, E. Sahin, D. Weisshaar, K. Wimmer, R. Winkler
Physics Faculty Publications
Intermediate-energy Coulomb excitation measurements are performed on the N≥40 neutron-rich nuclei 66, 68Fe and 64Cr. The reduced transition matrix elements providing a direct measure of the quadrupole collectivity B(E2; 2+1→ 0+1) are determined for the first time in 68Fe42 and 64Cr40 and confirm a previous recoil distance method lifetime measurement in 66Fe40. The results are compared to state-of-the-art large-scale shell-model calculations within the full fpgd neutron orbital model space using the Lenzi-Nowacki-Poves-Sieja effective interaction and confirm the results of the calculations that show …
System-Size Dependence Of Transverse Momentum Correlations At √ S N N = 62.4 And 200 Gev At The Bnl Relativistic Heavy Ion Collider, L. Adamczyk, J. K. Adkins, G. Agakishiev, M. M. Aggarwal, Z. Ahammed, I. Alekseev, J. Alford, S. Bültmann, I. Koralt
System-Size Dependence Of Transverse Momentum Correlations At √ S N N = 62.4 And 200 Gev At The Bnl Relativistic Heavy Ion Collider, L. Adamczyk, J. K. Adkins, G. Agakishiev, M. M. Aggarwal, Z. Ahammed, I. Alekseev, J. Alford, S. Bültmann, I. Koralt
Physics Faculty Publications
We present a study of the average transverse momentum (Pt) fluctuations and pt correlations for charged particles produced in Cu+Cu collisions at midrapidity for √sNN= 62.4 and 200 GeV. These results are compared with those published for Au+Au collisions at the same energies, to explore the system size dependence. In addition to the collision energy and system size dependence, the Pt correlation results have been studied as functions of the collision centralities, the ranges in Pt, the pseudorapidity η, and the azimuthal angle ϕ. The square root of the measured Pt correlations when scaled …
High-Spin Study Of The Shell Model Nucleus 88Y49, M. Bunce, P. H. Regan, V. Werner, C. W. Beausang, A. Anagnostatou, M. Bowry, R. J. Casperson, D. Chen, N. Cooper, P. Goddard, R. O. Hughes, G. Ilie, P.J.R. Mason, B. Pauerstein, M. W. Reed, T. J. Ross, E. C. Simpson
High-Spin Study Of The Shell Model Nucleus 88Y49, M. Bunce, P. H. Regan, V. Werner, C. W. Beausang, A. Anagnostatou, M. Bowry, R. J. Casperson, D. Chen, N. Cooper, P. Goddard, R. O. Hughes, G. Ilie, P.J.R. Mason, B. Pauerstein, M. W. Reed, T. J. Ross, E. C. Simpson
Physics Faculty Publications
The near-yrast structure of the near-magic, odd-odd nucleus, 8839Y49, has been studied into the high-spin regime. Investigations were performed at the Wright Nuclear Structure Laboratory, Yale University, using the 74Ge(18O,p3n) and 76Ge(18O,p5n) fusion-evaporation reactions at beam energies of 60 and 90 MeV, respectively. Gamma-ray energy coincidence analyses using both double (γ2) and triple (γ3) fold coincidences, together with angular correlation measurements, have been used to extend the previously reported level scheme to an excitation energy of 8.6 MeV and a …
Near-Threshold Neutral Pion Electroproduction At High Momentum Transfers And Generalized Form Factors, P. Khetarpal, Gerard P. Gilfoyle, Et. Al.
Near-Threshold Neutral Pion Electroproduction At High Momentum Transfers And Generalized Form Factors, P. Khetarpal, Gerard P. Gilfoyle, Et. Al.
Physics Faculty Publications
We report the measurement of near-threshold neutral pion electroproduction cross sections and the extraction of the associated structure functions on the proton in the kinematic range Q2 from 2 to 4.5 GeV2 and W from 1.08 to 1.16 GeV. These measurements allow us to access the dominant pion-nucleon s-wave multipoles E0+ and S0+ in the near-threshold region. In the light-cone sum-rule framework (LCSR), these multipoles are related to the generalized form factors G1π0p (Q2) and G2π0p (Q2). The data are compared to these …
Single Spin Asymmetry An In Polarized Proton–Proton Elastic Scattering At √S = 200 Gev, L. Adamczyk, G. Agakishiev, M. M. Aggarwal, Z. Ahammed, A. V. Alakhverdyants, I. Alekseev, J. Alford, C. D. Anson, D. Arkhipkin, E. Aschenauer, S. Bültmann, I. Koralt, D. Plyku
Single Spin Asymmetry An In Polarized Proton–Proton Elastic Scattering At √S = 200 Gev, L. Adamczyk, G. Agakishiev, M. M. Aggarwal, Z. Ahammed, A. V. Alakhverdyants, I. Alekseev, J. Alford, C. D. Anson, D. Arkhipkin, E. Aschenauer, S. Bültmann, I. Koralt, D. Plyku
Physics Faculty Publications
We report a high precision measurement of the transverse single spin asymmetry AN at the center of mass energy √s = 200 GeV in elastic proton–proton scattering by the STAR experiment at RHIC. The AN was measured in the four-momentum transfer squared t range 0.003 ⩽ | t | ⩽ 0.035 ( GeV / c ) 2 , the region of a significant interference between the electromagnetic and hadronic scattering amplitudes. The measured values of AN and its t-dependence are consistent with a vanishing hadronic spin-flip amplitude, thus providing strong constraints on the ratio of the …
Design Evolution And Properties Of Superconducting Parallel-Bar Rf-Dipole Detecting And Crabbing Cavities, S. U. De Silva, J. R. Delayen
Design Evolution And Properties Of Superconducting Parallel-Bar Rf-Dipole Detecting And Crabbing Cavities, S. U. De Silva, J. R. Delayen
Physics Faculty Publications
Deflecting/crabbing cavities serve a variety of purposes in different accelerator applications, primarily in separating a single beam into multiple beams and in rotating bunches for head-on collisions at the interaction point in particle colliders. Deflecting/crabbing cavities are also used for transverse and longitudinal emittance exchange in beams, x-ray pulse compression, and for beam diagnostics. Compact superconducting deflecting/crabbing cavities are under development due to strict dimensional constraints and requirements for higher field gradients with low surface losses. The TEM-like superconducting parallel-bar cavity supports low operating frequencies, thus making the design favorable for many of the deflecting/crabbing cavity applications. The design of …
Fluctuations Of Charge Separation Perpendicular To The Event Plane And Local Parity Violation In √ˢᴺᴺ = 200 Gev Au + Au Collisions At The Bnl Relativistic Heavy Ion Collider, L. Adamczyk, J. K. Adkins, G. Agakishiev, S. Bültmann, M. Zyzak, Star Collaboration
Fluctuations Of Charge Separation Perpendicular To The Event Plane And Local Parity Violation In √ˢᴺᴺ = 200 Gev Au + Au Collisions At The Bnl Relativistic Heavy Ion Collider, L. Adamczyk, J. K. Adkins, G. Agakishiev, S. Bültmann, M. Zyzak, Star Collaboration
Physics Faculty Publications
Previous experimental results based on data (~ 15 x 106 events) collected by the STAR detector at the BNL Relativistic Heavy Ion Collider suggest event-by-event charge-separation fluctuations perpendicular to the event plane in noncentral heavy-ion collisions. Here we present the correlator previously used split into its two component parts to reveal correlations parallel and perpendicular to the event plane. The results are from a high-statistics 200-GeV Au + Au collisions data set (57 x 106 events) collected by the STAR experiment. We explicitly count units of charge separation from which we find clear evidence for more charge-separation fluctuations …
Experimental Studies Of Di-Jets In Au + Au Collisions Using Angular Correlations With Respect To Back-To-Back Leading Hadrons, L. Adamczyk, G. Agakishiev, M. M. Aggarwal, Z. Ahammed, I. Koralt, Star Collaboration
Experimental Studies Of Di-Jets In Au + Au Collisions Using Angular Correlations With Respect To Back-To-Back Leading Hadrons, L. Adamczyk, G. Agakishiev, M. M. Aggarwal, Z. Ahammed, I. Koralt, Star Collaboration
Physics Faculty Publications
Jet-medium interactions are studied via a multihadron correlation technique ( called "2 + 1"), where a pair of back-to-back hadron triggers with large transverse momentum is used as a proxy for a di-jet. This work extends the previous analysis for nearly symmetric trigger pairs with the highest momentum threshold of trigger hadron of 5 GeV/c with the new calorimeter-based triggers with energy thresholds of up to 10 GeV and above. The distributions of associated hadrons are studied in terms of correlation shapes and per-trigger yields on each trigger side. In contrast with di-hadron correlation results with single triggers, the associated …
Elliptic Flow Of Identified Hadrons In Au + Au Collisions At √ˢᴺᴺ = 7.7- 62.4 Gev, L. Adamczyk, J. K. Adkins, G. Agakishiev, M. M. Aggarwal, S. Bültmann, Star Collaboration
Elliptic Flow Of Identified Hadrons In Au + Au Collisions At √ˢᴺᴺ = 7.7- 62.4 Gev, L. Adamczyk, J. K. Adkins, G. Agakishiev, M. M. Aggarwal, S. Bültmann, Star Collaboration
Physics Faculty Publications
Measurements of the elliptic flow, υ2, of identified hadrons (π±, , K±, , KOs, p, p¯, ɸ, Λ, Λ¯, Ξ-, Ξ¯+, Ω-, Ω¯+ in Au + Au collisions at √ˢᴺᴺ = 7.7, 11.5, 19.6, 27, 39, and 62.4 GeV are presented. The measurements were done at midrapidity using the time-projection chamber and the time-of-flight detectors of the Solenoidal Tracker at RHIC experiment during the beam-energy scan program at Relativistic Heavy Ion Collider. A significant difference in the υ2 values for particles and the corresponding antiparticles was observed at all transverse momenta for …
Deep Exclusive Π+ Electroproduction Off The Proton At Clas, K. P. Adhikari, M. J. Amaryan, R. P. Bennett, G. E. Dodge, S. E. Kuhn, M. Mayer, C. S. Nepali, H. Seraydaryan, L. B. Weinstein, J. Zhang
Deep Exclusive Π+ Electroproduction Off The Proton At Clas, K. P. Adhikari, M. J. Amaryan, R. P. Bennett, G. E. Dodge, S. E. Kuhn, M. Mayer, C. S. Nepali, H. Seraydaryan, L. B. Weinstein, J. Zhang
Physics Faculty Publications
The exclusive electroproduction of π + above the resonance region was studied using the CEBAF Large Acceptance Spectrometer (CLAS) at Jefferson Laboratory by scattering a 6GeV continuous electron beam off a hydrogen target. The large acceptance and good resolution of CLAS, together with the high luminosity, allowed us to measure the cross section for the γ * p → nπ + process in 140 (Q 2, x B , t) bins: 0.16 < x B < 0.58, 1.6 GeV2 < Q 2 < 4.5 GeV2 and 0.1 GeV2 < −t < 5.3 GeV2. For most bins, the statistical accuracy is on the order of a …
Measurement Of Transparency Ratios For Protons From Short-Range Correlated Pairs, Clas Collaboration, L. B. Weinstein, K. P. Adhikari, M. J. Amaryan, H. Baghdasaryan, G. E. Dodge, C. E. Hyde, S. E. Kuhn, M. Mayer, H. Seradaryan
Measurement Of Transparency Ratios For Protons From Short-Range Correlated Pairs, Clas Collaboration, L. B. Weinstein, K. P. Adhikari, M. J. Amaryan, H. Baghdasaryan, G. E. Dodge, C. E. Hyde, S. E. Kuhn, M. Mayer, H. Seradaryan
Physics Faculty Publications
Nuclear transparency, Tp(A), is a measure of the average probability for a struck proton to escape the nucleus without significant re-interaction. Previously, nuclear transparencies were extracted for quasi-elastic A(e,e′p) knockout of protons with momentum below the Fermi momentum, where the spectral functions are well known. In this Letter we extract a novel observable, the transparency ratio, Tp(A)/Tp(12C), for knockout of high-missing-momentum protons from the breakup of short-range correlated pairs (2N-SRC) in Al, Fe and Pb nuclei relative to C. The ratios were measured at momentum transfer Q2 ⩾1.5(GeV/c)2 and x …
Transverse Polarization Of Σ+ (1189) In Photoproduction On A Hydrogen Target In Clas, Clas Collaboration, C. S. Nepali, M. Amaryan, K. P. Adhikari, H. Baghdasaryan, S. Bültmann, N. Guler, C. E. Hyde, A. Klein, S. E. Kuhn, M. Mayer, H. Seraydaryan, B. Torayev, L. B. Weinstein
Transverse Polarization Of Σ+ (1189) In Photoproduction On A Hydrogen Target In Clas, Clas Collaboration, C. S. Nepali, M. Amaryan, K. P. Adhikari, H. Baghdasaryan, S. Bültmann, N. Guler, C. E. Hyde, A. Klein, S. E. Kuhn, M. Mayer, H. Seraydaryan, B. Torayev, L. B. Weinstein
Physics Faculty Publications
Experimental results on the Σ+(1189) hyperon transverse polarization in photoproduction on a hydrogen target using the CLAS detector at Jefferson Laboratory are presented. The Σ+(1189) was reconstructed in the exclusive reaction γ+p→K0S+Σ+(1189) via the Σ+→pπ0 decay mode. The K0S was reconstructed in the invariant mass of two oppositely charged pions with the π0 identified in the missing mass of the detected pπ+π− final state. Experimental data were collected in the photon energy range Eγ=1.0 –3.5 GeV (√s range 1.66–2.73 GeV). We observe a large negative polarization …
Beam Asymmetry Σ For Π+ And Π0 Photoproduction On The Proton For Photon Energies From 1.102 To 1.862 Gev, K. P. Adhikari, D. Adikaram, M. J. Amaryan, C. S. Nepali, Y. Prok, Clas Collaboration
Beam Asymmetry Σ For Π+ And Π0 Photoproduction On The Proton For Photon Energies From 1.102 To 1.862 Gev, K. P. Adhikari, D. Adikaram, M. J. Amaryan, C. S. Nepali, Y. Prok, Clas Collaboration
Physics Faculty Publications
Beam asymmetries for the reactions ˠp -> pπ0 and ˠp -> nπ+have been measured with the CEBAF Large Acceptance Spectrometer (CLAS) and a tagged, linearly polarized photon beam with energies from 1.102-1.862 GeV. A Fourier moment technique for extracting beam asymmetries from experimental data is described. The results reported here possess greater precision and finer energy resolution than previous measurements. Our data for both pion reactions appear to favor the SAID and Bonn-Gatchina scattering analyses over the older Mainz MAID predictions. After incorporating the present set of beam asymmetries into the world database, exploratory fits made with …
Cross Sections For The Ɣp → K*+Ʌ And Ɣp → K*+Σº Reactions Measured At Clas, K.P. Adhikari, M. J. Amaryan, C. E. Hyde, S. Koirala, M. Mayer, Clas Collaboration
Cross Sections For The Ɣp → K*+Ʌ And Ɣp → K*+Σº Reactions Measured At Clas, K.P. Adhikari, M. J. Amaryan, C. E. Hyde, S. Koirala, M. Mayer, Clas Collaboration
Physics Faculty Publications
The first high-statistics cross sections for the reactions ɣp → K*+Ʌ and ɣp → K*+Σº were measured using the CLAS detector at photon energies between threshold and 3.9 GeV at the Thomas Jefferson National Accelerator Facility. Differential cross sections are presented over the full range of the center-of-mass angles, and then fitted to Legendre polynomials to extract the total cross section. Results for the K*+Ʌ final state are compared with two different calculations in an isobar and a Regge model, respectively. Theoretical calculations significantly underestimate the K*+Ʌ total cross sections between 2.1 and 2.6 GeV, but are in better agreement …