1. Possibility of direct extraction of the transversitiy from polarized Drell-Yan measurement in COMPASS Transversity Drell-Yan for transverstiy transverse momentum dependent PDFs polarized Drell-Yan idea of the Drell-Yan measurement in COMPASS requirements to the apparatus summary Workshop on Hadron Structure at J-PARC, November 30 - December 2, 2005 KEK, Tsukuba, Ibaraki, Japan T.Iwata ( Yamagata University) on behalf of COMPASS collaboration

2. Transversity 1.momentum distribution 2.helicity distribution 3.transversity distribution longitudinal transverse transversity has never been determined in experiments accessible in SI-DIS with transversely polarized targets data available from HERMES, COMPASS, J-Lab need polarized fragmentation functions ( not well known) study ongoing in Belle ・ Nucleon quark structure completely described by 3 distribution functions ( at twist 2 level) T.Iwata @ Workshop on Hadron Structure at J-PARC, Nov. 30 – Dec. 2, 2005, KEK

3. Drell-Yan for Transversity double polarized Drell-Yan Advantage: no need of any fragmention functions allows direct extraction of transverstiy GSI: But, a big challenge experimentally Possible T.Iwata @ Workshop on Hadron Structure at J-PARC, Nov. 30 – Dec. 2, 2005, KEK Drell-Yan is alternative way to access transversity

4. Single polarized Drell-Yan single polarized Drell-Yan less difficut experimentally Transversity accompanied with T-odd PDF ( one of the transvese momentum dependent PDFs) Unique environment of COMPASS polarized target hadron beam high rate trackers muon identification A.Sissakian et al., Phys. Rev. D72, 054027 (2005) T.Iwata @ Workshop on Hadron Structure at J-PARC, Nov. 30 – Dec. 2, 2005, KEK Two stages RICH High rate trackers Ecal, Hcal Muon filters COMPASS setup Polarized target long. & trans. pol Beam: muon & hadrons(  /p) COMMON Apparatus for muon & hadron programs

5. Transverse momentum dependent PDFs Nucleon Parton number density Nucleon unpol. long. pol.trans. pol. unpol. long. pol. trans. pol. Quark Sivers helicity transversity T-odd survive after integration over k T T.Iwata @ Workshop on Hadron Structure at J-PARC, Nov. 30 – Dec. 2, 2005, KEK T-odd Boer- Mulders

6. Unpolarized-Drell-Yan q T weighted angular distribution (q T :transvese momentum of virtual photon) T.Iwata @ Workshop on Hadron Structure at J-PARC, Nov. 30 – Dec. 2, 2005, KEK A.Sissakian et al., Phys. Rev. D72, 054027 (2005) V.Barone et al., Phys. Rep. 359 (2002)1-168 How to extract transversity in DY measurement? The ider is based on unpolarized Drell-Yan case lepton pair CM frame

7. Coefficient of COS2  term 1 st moment of the PDFs: T.Iwata @ Workshop on Hadron Structure at J-PARC, Nov. 30 – Dec. 2, 2005, KEK number densities (well known) Boer-Mulder PDF(T-odd) for anti-q in  Boer-Mulder PDF(T-odd) for q in proton

8. Single Spin Asymmetry : azimuthal angle of the target spin vector : target spin vector q T weighted single spin asymmetry for T.Iwata @ Workshop on Hadron Structure at J-PARC, Nov. 30 – Dec. 2, 2005, KEK Boer-Mulder PDF(T-odd) for anti-q in  transversity single polarized Drell-Yan case

9. Simplidied equations neglect s-quark, sea quark in proton, and d-quark contributions (d-quark originally suppressed due to its charge) known to be extracted given from T.Iwata @ Workshop on Hadron Structure at J-PARC, Nov. 30 – Dec. 2, 2005, KEK Boer-Mulder PDF(T-odd) for anti-u in  transversity expressions with only u-quark PDFs known transversity 1 2 3 1 1 3

10. Extraction in single exp. I Additonal assumption based on Boer’s model Phys.Rev. D60, 014012 (1999) E615 @ Fermilab anomalously large cos2  dependence observed Naive Drell-Yan thery predicts Phys. Rev. D39 (1989) 92 Boer’s Model explained it with transverse momentum dependent PDF (at LO) T.Iwata @ Workshop on Hadron Structure at J-PARC, Nov. 30 – Dec. 2, 2005, KEK pQCD (LO,NLO) not explained it

11. Extraction in single exp. II at the point With the assumption, the observables are rewritten only with the PDFs for proton T.Iwata @ Workshop on Hadron Structure at J-PARC, Nov. 30 – Dec. 2, 2005, KEK Boer-Mulder PDF (T-odd) for proton transversity unknown PDFs 1 2 1 2

12. Counting rate in COMPASS Beam: 100 GeV  - Target: 60 g/cm 2 NH 3 Luminosity: Cross section value: Acceptance : Expected rate for DY: Thus 0.08 events/spill (4000 spills/day)  320 events/day Total statistics: (SPS eff=80%) 120 days  30k events/year T.Iwata @ Workshop on Hadron Structure at J-PARC, Nov. 30 – Dec. 2, 2005, KEK Very preliminary!

13. Comparison of running conditions current conditionDrell-Yan beam pol   160 GeV  - 100 GeV intensity 2x10 8   /spill(4.8s)(4.2x10 7   /s)4.8x10 8  - /spill(4.8s)(1.0x10 8  - /s) pol. target 6 LiD 60 g/cm 2 (NH 3 60 g/cm 2 in 2006 ) NH 3 60 g/cm 2 polarization modelongitudinal & transverse transverse total event rate~10 5 /s1x10 8 /s charged hadrons/event~ 4~ 6 T.Iwata @ Workshop on Hadron Structure at J-PARC, Nov. 30 – Dec. 2, 2005, KEK current condition with  beam Drell-Yan with  beam

14. Requirements to the apparatus Spectrometer: high rate capability required ( for trackers near the target) upgrading SciFi, GEM, Micromegas no need of complete particle ID(only muon ID with muon filters) Polarized target:  heat load increase by x ~ 10 ( 0.5mW, ~ 2mW/spill) runing in frozen spin mode( for transverse polarization) better cooling efficiency needed to maintain its polarization T.Iwata @ Workshop on Hadron Structure at J-PARC, Nov. 30 – Dec. 2, 2005, KEK

15. Improvements of PT N.Doshita et al., NIM A 526 (2004) 138-143 Relaxation time(NH3) : T 1 =400 hours @ 60mK, 0.4T, The dilution refrigerator can manage the heat load (sufficient cooling power) small beads or thin sheet NH3 in SMC, (2006 COMPASS) Maximum beam intensity vs. bead diameter T.Iwata @ Workshop on Hadron Structure at J-PARC, Nov. 30 – Dec. 2, 2005, KEK Problem: removing heat from the material DNP mode frozen spin mode larger surface area  bottle neck: Kapitza resistance heat from target bead

16. Summary Drell-Yan process is a powerful tool to study the transverstiy and the accompanying T-odd kt dependent PDFs. COMPASS offers unique environment for the single plarized Drell-Yan measurement. The design of the measurment is underway in COMPASS collaboration. Requirements to the apparatus were shown in this talk. T.Iwata @ Workshop on Hadron Structure at J-PARC, Nov. 30 – Dec. 2, 2005, KEK

17. Backup slides

18. Boer’s Model Phys.Rev. D60, 014012 (1999)

19. given from

20. Accessible kinematics in COMPASS