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Open Access. Powered by Scholars. Published by Universities.®

University of Kentucky

2016

Protons

Articles 1 - 3 of 3

Full-Text Articles in Physical Sciences and Mathematics

ΠN And Strangeness Sigma Terms At The Physical Point With Chiral Fermions, Yi-Bo Yang, Andrei Alexandru, Terrence Draper, Jian Liang, Keh-Fei Liu Sep 2016

ΠN And Strangeness Sigma Terms At The Physical Point With Chiral Fermions, Yi-Bo Yang, Andrei Alexandru, Terrence Draper, Jian Liang, Keh-Fei Liu

Physics and Astronomy Faculty Publications

Lattice QCD calculations with chiral fermions of the πN sigma term σπN and strangeness sigma term σπN including chiral interpolation with continuum and volume corrections are provided in this work, with the excited-state contaminations subtracted properly. We calculate the scalar matrix element for the light/strange quark directly and find σπN = 45.9(7.4)(2.8)  MeV, with the disconnected insertion part contributing 20(12)(4)%, and σπN = 40.2(11.7)(3.5)  MeV, which is somewhat smaller than σπN. The ratio of the strange/light scalar matrix elements is y = 0.09(3)(1).


Measurement Of The Transverse Single-Spin Asymmetry In P+PW±/Z0 At Rhic, L. Adamczyk, James K. Adkins, G. Agakishiev, M. M. Aggarwal, Z. Ahammed, I. Alekseev, A. Aparin, D. Arkhipkin, E. C. Aschenauer, A. Attri, G. S. Averichev, X. Bai, V. Bairathi, A. Banerjee, R. Bellwied, A. Bhasin, A. K. Bhati, P. Bhattarai, J. Bielcik, J. Bielcikova, L. C. Bland, I. G. Bordyuzhin, J. Bouchet, J. D. Brandenburg, A. V. Brandin, I. Bunzarov, J. Butterworth, H. Caines, M. Calderón De La Barca Sánchez, J. M. Campbell, Renee H. Fatemi, Suvarna Ramachandran Apr 2016

Measurement Of The Transverse Single-Spin Asymmetry In P↑+P→W±/Z0 At Rhic, L. Adamczyk, James K. Adkins, G. Agakishiev, M. M. Aggarwal, Z. Ahammed, I. Alekseev, A. Aparin, D. Arkhipkin, E. C. Aschenauer, A. Attri, G. S. Averichev, X. Bai, V. Bairathi, A. Banerjee, R. Bellwied, A. Bhasin, A. K. Bhati, P. Bhattarai, J. Bielcik, J. Bielcikova, L. C. Bland, I. G. Bordyuzhin, J. Bouchet, J. D. Brandenburg, A. V. Brandin, I. Bunzarov, J. Butterworth, H. Caines, M. Calderón De La Barca Sánchez, J. M. Campbell, Renee H. Fatemi, Suvarna Ramachandran

Physics and Astronomy Faculty Publications

We present the measurement of the transverse single-spin asymmetry of weak boson production in transversely polarized proton-proton collisions at √s = 500  GeV by the STAR experiment at RHIC. The measured observable is sensitive to the Sivers function, one of the transverse-momentum-dependent parton distribution functions, which is predicted to have the opposite sign in proton-proton collisions from that observed in deep inelastic lepton-proton scattering. These data provide the first experimental investigation of the nonuniversality of the Sivers function, fundamental to our understanding of QCD.


Stochastic Model With Low Mode Substitution For Nucleon Isovector Matrix Elements, Yi-Bo Yang, Andrei Alexandru, Terrence Draper, Ming Gong, Keh-Fei Liu Feb 2016

Stochastic Model With Low Mode Substitution For Nucleon Isovector Matrix Elements, Yi-Bo Yang, Andrei Alexandru, Terrence Draper, Ming Gong, Keh-Fei Liu

Physics and Astronomy Faculty Publications

We introduce a stochastic method with low-mode substitution to evaluate the connected three-point functions. The isovector matrix elements of the nucleon for the axial-vector coupling g3A, scalar couplings g3S and the quark momentum fraction ⟨xu−d are calculated with overlap fermion on 2 + 1 flavor domain-wall configurations on a 243 × 64 lattice at mπ = 330  MeV with lattice spacing a = 0.114  fm.