High-energy hadron physics at J-PARC Wen-Chen Chang 章文箴 Institute of Physics, Academia Sinica, Taiwan KEK theory center workshop on Hadron physics with high-momentum hadron beams at J-PARC January 15-18, 2013 Outline: Beam configuration Pion-induced Drell-Yan experiments What we have learned and wish to learn Pion structure Boer-Mulders function vs. QCD vacuum effect Experimental requirements Summary Outline: Beam configuration Pion-induced Drell-Yan experiments What we have learned and wish to learn Pion structure Boer-Mulders function vs. QCD vacuum effect Experimental requirements Summary

R. Muto, KEK 2

3

4

Beam Configuration Primary 30-GeV proton beam at /s. Secondary beam: ◦ Pion: GeV at 10 8 /s. ◦ Kaon: GeV at /s. ◦ Anti-proton: 5-10 GeV at 10 6 /s. 5

Physics Programs Primary 30-GeV proton beam: ◦ E16: nuclear modification of vector mesons (S. Yokkaichi, Jan 17 th ). ◦ E21:  -e conversion ◦ Proton-induced Drell-Yan process: sea quark distributions of nucleon at large x and spin physics (Y. Goto, Jan 18 th ). Secondary beam: ◦ Pion-induced DY process:  Exclusive process to explore the pion.  Violation of Lam-Tung relation in Drell-Yan process.  Valence d/u of nucleons at large x.  Intrinsic charm of nucleons.  Flavor dependence of EMC effect. ◦ Charmed Baryon (K. Ozawa, Jan 16 th ) ◦ … 6

Pion-induced Drell-Yan Process Uniqueness: ◦ Valence anti-quark in the pion: pion beam is more effective in producing large-mass DY than proton beam. ◦ Sensitive to the valence quark of nucleon target. ◦ To explore pion partonic structure. Experiments: (angular distributions) ◦ FNAL CIP (1979) (252-GeV  ) ◦ CERN NA10 (1986) (140, 194, 286-GeV  ) ◦ FNAL E615 (1989) (252-GeV and 80-GeV  ; 252-GeV  +) 7

CIP (PRL 42, 944, (1979)) Atomic Mass Number Dependence  =1.12  =1.02 Consistent with quark-antiquark annihilation DY model. 8

Angular Distribution of Lepton Pair Collins-Soper Frame 9

CIP (PRL 42, 948, (1979)) Transversely Polarized Photon 10

CIP (PRL 43, 1219, (1979)) Longitudinally Polarized Photon at large x 1 11

E615 (PRD 39, 92 (1989)) Higher Twist Effect 12

Berger and Brodsky (PRL 42, 940, (1979)) Higher Twist Effect at large x 1 13

Brandenburg et al. (PRL 73, 939 (1994)) Pion Distribution Amplitude Pion distribution amplitude: distribution of LC momentum fractions in the lowest-particle number valence Fock state. 14

Brandenburg et al. (PRL 73, 939 (1994)) Pion Distribution Amplitude  :E615 15

A. Brandenburg et al. (Phys. Rev. D 76, (2007)) Pion Distribution Amplitude 16

A. P. Bakulev et al. (Phys. Rev. D 76, (2007)) Sensitivity to Pion DA 17  2 -(1- )

X-G Wu and T. Huang (Phys. Rev. D 82, (2010)) Pion Distribution Amplitude From Pion- Photon Transition Form Factor 18

Exclusive Pion-Induced Drell-Yan Process DA characterizes the minimal valence Fock state of hadrons. DA of pion are also explored by pion-photon transition form factor in Belle and Barbar Exps. TDA characterizes the next-to- minimal valence Fock state of hadrons. TDA of pion-nucleon is related to the pion cloud of nucleons. Bernard Pire, IWHS

Lam and Tung (PRD 18, 2447, (1978)) Lam-Tung Relation 20

NA10 (Z. Phys. C 37, 545 (1988)) Decay Angular Distributions pQCD 21

NA10 (Z. Phys. C 37, 545 (1988)) First data with Deuterium Target 22

NA10 (Z. Phys. C 37, 545 (1988)) Violation of Lam-Tung Relation 140 GeV/c 194 GeV/c 286 GeV/c J.C. Peng Violation of LT relation suggests mechanisms of non-perturbative origins. 23

E615 (PRD 39, 92 (1989)) Violation of LT Relation 24

D. Boer 25

D. Boer 26

D. Boer 27

D. Boer Chromo-magnetic Sokolov-Ternov effect: spin-flip gluon synchrotron emission leading to a correlated polarization of q and qbar. 28

Brandenburg, et. al (Z. Phy. C60,697 (1993)) QCD Vacuum Effect On average no quark polarization, but a spin correlation between an annihilating quark and antiquark is caused by nontrivial QCD vacuum. 29

Boer (PRD 60, (1999)) Hadronic Effect, Boer-Mulders Functions 30

D. Boer 31

E866 (PRL 99 (2007) ; PRL 102 (2009) ) Consistency of LT relation for DY events in pd, pp 32

E866 (PRL 99 (2007) ) Azimuthal cos2 Φ Distribution of DY events in pd ν(π - W  µ + µ - X)~ [valence h 1 ┴ (π)] * [valence h 1 ┴ (p)] ν(pd  µ+µ-X) ~ [valence h 1 ┴ (p)] * [sea h 1 ┴ (p)] Sea-quark BM functions are much smaller than valence quarks 33

E866 (PRL 102 (2009) ) Azimuthal cos2 Φ Distribution of DY events in pp ν(pp  µ+µ-X)~ ν(pd  µ+µ-X) Presence of higher-order QCD effect at high p T 34

CDF (PRL 106, (2011)) Angular Distribution of p-pbar DY at Z pole A good agreement with the Lam-Tung relation A 0 -A 2 =0 35

Boer-Mulders functions from unpolarized pD and pp Drell-Yan Z. Lu and I. Schmidt, PRD 81, (2010) V. Barone et al., PRD 82, (2010) Sign of BM functions and their flavor dependence? 36

Z. Lu et al. (PLB 639 (2006) 494) Flavor separation of the Boer–Mulders function MIT Bag Model Spectator Model Large Nc limit Deuterium target 37

J.C. Peng 38

J.C. Peng 39

A. Accardi et al. Phys. Rev. D 84, (2011) 40

J. Arrington et al. (PRL 108, (2012)) Uncertainties in F 2 n /F 2 p Deuteron wave function at short distances (Fermi motion) Nucleon off-shell effect Nuclear correction 41

J. Arrington et al. (PRL 108, (2012)) Uncertainties in d/u 42

Helium/DME at 80/20 ratio beam 140 µm Experimental Setup II: BoNuS RTPC Fit RTPC points to determine helix of proton trajectory. Momentum determined from track curvature in solenoid field. dE/dx along track in RTPC also provides momentum information. Solenoid Magnet BoNuS RTPC Moller Catcher To BoNuS RTPC to CLAS p n M. Eric Christy 43

Neutron F 2 Structure Function via Spectator Tagging PRL 108, (2012) 44

Pion-Induced DY Without OR With Spectator Tagging 45

Experimental Requirements Beam: ◦ Hadron-type separation is preferred. ◦ High momentum: GeV  beam. ◦ High flux: >10 8 /sec ◦ Similar interesting physics to be explored by other secondary beams like K and pbar. Target: ◦ Long liquid hydrogen and deuterium target. ◦ Nuclei target. Detector: ◦ Large-acceptance spectrometers: detecting the di-lepton pairs or the recoiled protons in the very forward and slightly backward directions. ◦ Good mass resolution: precise measurement of di-lepton mass to ensure an exclusive reaction via the missing-mass technique. ◦ Hadron absorber : if DY process is to be characterized by the muon pairs. 46

Summary Pion-induced DY program in the high- momentum beamline of J-PARC will offer important understanding on the aspects of ◦ QCD ◦ TMD PDF (Boer-Mulders Function) ◦ Pion structure ◦ Nucleon Similar programs could be carried out using the kaon and anti-proton beam. Spectrometer with a large acceptance and good mass resolution is required. 47