Azimuthal transverse single-spin asymmetries of inclusive jets and charged pions within jets from polarized-proton collisions at s=500  GeV

L Adamczyk,D Kalinkin,P Tribedy,S Mizuno,L Kochenda,C Perkins,D Mallick,J Zhao,T Todoroki,S Luo,R Sikora,P Federicova,X Dong,S Das,K Yip,Y Wang,J Thäder,I Bunzarov,C Li,Z Ahammed,B Stringfellow,C Yang,Z Ye,Z Zhang,D Smirnov,T Lin,D Mishra,A Kechechyan,J Fujita,S Chattopadhyay,K Jiang,S Fazio,N Kulathunga,W Christie,M Strikhanov,K Meehan,F Videbæk,A Vossen,A Jentsch,Z Tang,S Trentalange,K Kang,L Ruan,L Wen,Z Chang,X Huang,Y Guo,M Zyzak,D Olvitt,A Chatterjee,K Krueger,T Tarnowsky,Z Feng,M Shao,J Sandweiss,R Aoyama,J Ewigleben,P Sorensen,S Esumi,Md Nasim,J Porter,A Aparin,D Arkhipkin,H Pei,L Didenko,K Oh,M Saur,W Zha,N Herrmann,M Calderón De La Barca Sánchez,P Seyboth,J Cheng,N Smirnov,A Hirsch,Y Li,K Kauder,A Gupta,F Wang,S Mioduszewski,A Gibson,S Ramachandran,P Bhattarai,E Finch,J Bryslawskyj,D Tlusty,S Horvat,J Pluta,K Poniatowska,H Caines,T Sugiura,A Tawfik,R Ma,J Zhang,S Heppelmann,C Kim,L He,P Filip,A Harlenderova,B Mohanty,J Schambach,J Bouchet,A Kisiel,S Zhang,O Rusnakova,A Ogawa,E Shahaliev,R Pak,R Seto,S Yang,J Putschke,I Alekseev,Y Panebratsev,R Bellwied,G Wang,G Odyniec,W Xie,A Hamed,B Srivastava,M Tokarev,J Deng,T Kollegger,C Dilks,Y Fisyak,A Bhasin,B Huang,M Lomnitz,Z Xu,J Lidrych,A Quintero,J Butterworth,P Huo,M Kocmanek,R Lacey,N Schmitz,G Nigmatkulov,M Posik,W Li,D Kapukchyan,I Upsal,G Xie,J Jia,D Cebra,T Ullrich,X Luo,T Nonaka,B Surrow,N Yu,P Liu,C Markert,S Kabana,N Magdy,Y Wu,L Krauth,L Yi,N Elsey,N Xu,A Taranenko,X Li,D Grosnick,X Zhu,G Igo,J Engelage,M Sergeeva,R Fatemi,M Simko,N Chankova-Bunzarova,M Cherney,G Agakishiev,N Shah,X Chen,Y Zhang,M Nie,Z Shi,A Behera,G Van Buren,T Huang,D Keane,I Kisel,V Bairathi,J Kvapil,H Wieman,T Niida,G Eppley,S Singha,J Seger,O Evdokimov,P Federic,S Margetis,L Kumar,G Contin,G Van Nieuwenhuizen,W Guryn,I Chakaberia,S Jowzaee,S Salur,H Zbroszczyk,C Zhou,B Pawlik,R Witt,H Liu,B Summa,A Lebedev,J Lauret,R Majka,O Eyser,R Reed,Y Liu,Y Pandit,G Webb,P Chaloupka,L Ma,F Liu,Q Yang,W Solyst,R Esha,A Attri,A Schmah ,Xiaozhi Bai ,X P Zhang ,Q H Xu ,T Ljubičić ,T K Nayak ,J H Kwasizur ,B A Trzeciak ,M Przybycień ,A Vasiliev ,S A Voloshin ,H Z Huang ,Z H Zhu ,Yi Yang ,П Кравцов ,J W Harris ,Zhong Chen ,J C Mei ,J H Chen ,J Bielčíková ,J C Webb ,Д А Морозов ,P V Shanmuganathan ,J D Brandenburg ,David J Stewart ,D M Anderson ,A F Kraishan ,M A Lisa ,S W Wissink ,M Šumbera ,D S Gunarathne ,R Lednický ,J M Campbell ,I G Bordyuzhin ,R S Longacre ,M J Skoby ,H G Ritter ,W B Schmidke ,J H Lee ,H M Spinka ,H S Matis ,J M Landgraf ,N Sahoo ,K D Landry ,D S Brown ,J Roberts ,S S Shi ,P K Sahu ,S B Nurushev ,B S Page ,O V Rogachevskiy ,M K Mustafa ,K N Barish ,Z W Miller ,Y K Sun ,M U Ashraf ,J B Zhang ,A R Timmins ,L C Bland ,Jun Xu ,L K Kosarzewski ,David G Mayes ,N N Ajitanand ,Xiao Zhang ,Martin Girard ,R E Tribble ,C Flores ,J Bielčík ,A A Derevschikov ,H J Crawford ,N K Pruthi ,Alexandre Alarcon Do Passo Suaide ,H W Ke ,Y Xu ,G D Westfall ,S Vokál ,M M Aggarwal ,S K Tripathy ,J R Adams ,G S Averichev ,I M Deppner ,D P Kikoła ,T G Dedovich ,X M Sun ,W J Llope ,A H Tang ,E G Judd ,J M Nelson ,J Rusňák ,D B Nemes ,J C Dunlop ,Y G ,N G Minaev ,L G Efimov ,T D S Stanislaus ,J K Adkins ,W Q Shen ,Vitaly Okorokov ,E P Sichtermann ,A I Hamad ,J D Roth ,A K Bhati ,M M Mondal ,W W Jacobs ,B R Schweid ,M J Rehbein ,J Fedorišin ,C A Gagliardi ,I K Yoo ,Long Zhou ,E C Aschenauer ,O D Tsai ,A V Brandin ,F J M Geurts ,Ł Fulek ,J L Drachenberg ,L V Nogach ,D G Underwood ,J L Romero ,J H Thomas ,T J Humanic ,R L Ray ,Q Shou ,G L ,J E Draper ,Z H Khan ,D N Svirida

doi:10.1103/physrevd.97.032004

Abstract

We report the first measurements of transverse single-spin asymmetries for inclusive jet and jet + $\pi^{\pm}$ production at midrapidity from transversely polarized proton-proton collisions at $\sqrt{s} = 500$ GeV. The data were collected in 2011 with the STAR detector sampled from 23 pb$^{-1}$ integrated luminosity with an average beam polarization of 53%. Asymmetries are reported for jets with transverse momenta $6 < p_{T, jet} < 55$ GeV/c and pseudorapidity $|\eta| < 1$. Presented are measurements of the inclusive-jet azimuthal transverse single-spin asymmetry, sensitive to twist-3 initial-state quark-gluon correlators; the Collins asymmetry, sensitive to quark transversity coupled to the polarized Collins fragmentation function; and the first measurement of the "Collins-like" asymmetry, sensitive to linearly polarized gluons. Within the present statistical precision, inclusive-jet and Collins-like asymmetries are small, with the latter allowing the first experimental constraints on gluon linear polarization in a polarized proton. At higher values of jet transverse momenta, we observe the first non-zero Collins asymmetries in polarized-proton collisions, with a statistical significance of greater than $5\sigma$. The results span a range of x similar to results from SIDIS but at much higher $Q^{2}$. The Collins results enable tests of universality and factorization-breaking in the transverse momentum-dependent formulation of perturbative quantum chromodynamics.

Highlights

The partonic structure of the nucleon at leading twist in a collinear picture can be described by three parton distribution functions (PDFs): the unpolarized parton distribution, fðx; Q2Þ; the parton helicity distribution, Δfðx; Q2Þ; and the transversity distribution, h1ðx; Q2Þ [1]
We report the first measurements of transverse single-spin asymmetries for inclupsivffiffie jet and jet þ πÆ production at midrapidity from transversely polarized proton-proton collisions at s 1⁄4 500 GeV
Final results for the inclusive-jet, Collins, and Collinslike asymmetries are presented in Figs. 9 through 13

Summary

Introduction

The partonic structure of the nucleon at leading twist in a collinear picture can be described by three parton distribution functions (PDFs): the unpolarized parton distribution, fðx; Q2Þ; the parton helicity distribution, Δfðx; Q2Þ; and the transversity distribution, h1ðx; Q2Þ [1]. Helicity distribution constraints have required observables from the interaction of spin-polarized probes. Recent global analyses have combined data from polarized deep-inelastic scattering (DIS), semi-inclusive DIS (SIDIS), and proton-proton experiments to extract helicity distributions for quarks, antiquarks, and gluons [3–6]. Of the three leading-twist PDFs, transversity, which describes the transverse polarization of quarks inside a transversely polarized nucleon, has proven the most difficult to probe. This is due to its chiral-odd nature that requires transversity to couple to another chiral-odd quantity in order to be observed

Methods

Results

Conclusion