1 / 21

Studies of TMDs with CLAS & CLAS12

Studies of TMDs with CLAS & CLAS12. P. Rossi Laboratori Nazionali di Frascati - INFN On behalf of the CLAS Collaboration. Introduction SIDIS experiments @ JLab with CLAS Results @ 6 GeV CLAS12 and TMDs studies @ 12 GeV Conclusions. May 18-21, 2010
TJNAF
-Newport News, Virginia USA.

lotta
Download Presentation

Studies of TMDs with CLAS & CLAS12

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Studies of TMDs with CLAS & CLAS12 P. Rossi Laboratori Nazionali di Frascati - INFN On behalf of the CLAS Collaboration • Introduction • SIDIS experiments @ JLab with CLAS • Results @ 6 GeV • CLAS12 and TMDs studies @ 12 GeV • Conclusions May 18-21, 2010
TJNAF
-Newport News, Virginia USA

  2. Introduction Nucleon is a complex object • Our goal is: • Study its STRUCTURE  3D image (coord. & mom.)  Spin origin  Flavor content • Understand CONFINEMENT Transverse Momentum dependent parton Distribution functions (TMDs) are relevant for all these issues

  3. k’, E’ Inclusive DIS experiments - 2D image (collinear approx.) - unable to account for all the nucleon spin k, E Semi-Inclusive DIS experiments - 3D image in momentum space - Access quark orbital momentum Lq h FF X DF • Observable are Single Spin Asymmetry (SSAs) which are due to correlations betweentransverse momentumof quarks (k) and the spinof the quark/nucleon moments of  s SIDIS experiments and SSAs ‘

  4. CLAS CLAS at JLab perfectly matches all this requirements Lumi ~1034cm-2sec-1 e- A C B Data taken in 2001/2005/2009 Data in 2011? Jefferson Lab and CLAS e p e’ h X high intensity beam with high polarization polarized targets high acceptance for the hadron 20 cryomodules Beam: continuous Energy: 0.8 - 5.7 GeV Current: 0.1nA - 200 A Polarization: 75-85%

  5. Polarized target (NH3/ND3)  Pol.NH3, ND3 targets <PH> =0.75, <PD>=0.3 Longitudinal polarization Inner Calorimeter (424 PbWO4 crystals) to detect high energy photons at forward lab angles. IC Experimental configuration Experimental configuration for unpolarized/long.polarized target

  6. Longitudinally Polarized NH3/ND3 (no IC, ~5 days)2001 AUL, ALL: arXiv:1003.4549 Submitted to PRL Longitudinally Polarized NH3/ND3 with IC 60 days2009 New data under analysis Experiment E05-113 0 BSAAnalysis completed Analysis note under coll. review Unpolarized H with IC ~60 days2005 Transversely Polarized HD-Ice (no IC, 25 days) 2011 (?) Experiment in preparation SIDIS with CLAS @ 6 GeV ep e’pX • DIS kinematics: Q2>1 GeV2, W2>4 GeV2, y<0.85 Q2

  7. U L U L U L U L Pion SSA with unpol./long. Polarized target • CLAS program: extraction of leading twist and higher twist TMDs • quark-gluon-quark correlations responsible forazimuthal moments of h.t. 0/+/-TSA 0BSA PT-dependence

  8. Preliminary ~10% of E05-113 data Longitudinal pol. Target Kotzinian-Mulders asymmetry Transversely polarized quarks in a longitudinally polarized nucleon e p e’p X • ~5 days data taking • AUL over the full kinematics • Fitting function: • p1sin+p2sin2 p1= 0.046±0.016 p2=-0.060±0.016 p1= 0.059±0.018 p2=-0.010±0.019 p1= 0.047±0.010 p2=-0.042±0.010 H. Avakian et al. arXiv:1003.4549 + • No indication of Collins effect forp0 • Non-zero negative asymmetry for p+/-

  9. curves, cQSM from Efremov et al H. Avakian et al. arXiv:1003.4549 Projected results for Exp. E05-113 Longitudinal pol. Target Kotzinian-Mulders asymmetry • Total good events accumulated on proton with CLAS in 3 months ~ 10 times statistics accumulated by HERMES in 2 years • Analysis Topics :+/-/0 AUL(sin2), ALL, ALU(sin) • +/- AUL(sin2)

  10. Projected results for Exp. E05-113 + - 0 R=0.40 R=0.68 R=1.0 Different width of TMDs of quarks with different flavor and polarizations f1=0.25 GeV2 • Data shows slight preference for R<  • New experiment with 10 times more data will study the PT-dependence for different quark helicities and flavors for bins in x Longitudinal pol. Target: A1-PT dependence Anselmino et. al PRD74,074015(2006) H. Avakian et al. arXiv:1003.4549

  11. BSA ~ sin insensitive to other harmonics BSA: Asymmetry extraction and fitting for 0 e p e’p X

  12. Preliminary Preliminary M Aghasyan, LNF-INFN M Aghasyan, LNF-INFN • Drop with PT below 1 GeV/c Preliminary • Comparable BSA for p0 andp+ • Small Collins type contributions for p+? Main contribution? M Aghasyan, LNF-INFN 0 BSA Asymmetry results • ALU in agreement with HERMES data

  13. Transversely polarized HD-ice target • Target used by LEGS at BNL with photon beam • Pros • Small field (∫Bdl~0.005-0.05Tm) • Small dilution factor • Less radiation length • Less nuclear background • Wider acceptance • much better FOM, especially for deuteron • Cons • HD target is highly complex and there is a need for redundancy due to the very long polarizing times (months). • Need to demonstrate that the target can remain polarized for long periods with an electron beam with currents of order of 1-2 nA • The target is now at Jlab and all equipment moved to the new HDice lab • HDiceinstallation in the Hall January 2011 • photon run with HD-ice March 2011 • test run with e- end of Apr 2011 • physics run with e- t.b.d. Tentative schedule

  14. curves from Yuan, Efremov,Collins Projected results for 30 days of CLAS at 6 GeV in 2011 (PT=75% L=5.1033cm-2s-1 ) CLAS will provide a superior measurements of Sivers asymmetry at large x, where the effect is large and models unconstrained by previous measurements. TMDs with transversly polarized target Sivers Sivers TMD Collins transversity TMD Collins FF pretzelosity TMD Collins FF

  15. TMDs on a transversely pol. neutron in HALL A • Beam: 6 GeV, 15 mA (target limit) • Neutron Target: • High pressure polarized 3He, 50 mg/cm2, Pol. ~ 60% • Hadron Detection: HRS Left Ph = 2.4 GeV/c, p/K ID • Kinematic Region • <Q2> = 2.2 GeV2, x = 0.130.4, z ~ 0.5 p+/- e- • Analysis underway Hall A 1 month data taking: statistical errors comparable to HERMES(3 years)/COMPASS(2 years)

  16. Summary of experimental results • Transverse degrees of freedom led to a bunch of new, more complex, distribution and fragmentation functions • Unpolarized and polarized data from different Laboratories are giving a first look at these new functions • A new generation of experiments is necessary to fully exploit the properties of TMDs, with • - wide kinematic coverage • - high luminosity • - high polarization • - high capability of final hadron separation

  17. LTCC DC R1, R2, R3 CHL-2 PCAL CLAS12 Beam Current: 90 µA Max Pass energy: 2.2 GeV Max Enery Hall A,B,C: 11 GeV Solenoid 5T • Primary goal of experiments using CLAS12: • study of the internal nucleon dynamics by accessing GPDs & TMDs  detector tuned for studies of exclusive and semi-inclusive reactions in a wide kinematic range. • Large acceptance detector and high luminosity capabilities EC HTCC FTOF L = 1035 cm-2s-1 CEBAF @ 12 GeV and CLAS12 May 2012 6 GeV Accelerator Shutdown starts May 2013 Accelerator Commissioning starts 2013-2015 Pre-Ops (beam commissioning)

  18. We are here! 1 GeV2 CTEQ5M parton distribution Q=5 GeV x f(x,Q) x 12 GeV Kinematical coverage • Kinematic suppression • small cross section Study of high xB domain requires high luminosity

  19. E12-06-112:Pion SIDIS E12-09-008: KaonSIDIS U E12-07-107:Pion SIDIS E12-09-009: KaonSIDIS L T LOI12-06-108: Pion SIDIS LOI12-09-004: KaonSIDIS q N TMDs program @ 12 GeV in Hall B PAC approved experiments & LoI • Complete program of TMDs studies for pions and kaons • Kaon measurements crucial for a better understanding of the TMDs “kaon puzzle” • Kaon SIDIS program requires an upgrade of the CLAS12 detector PID RICH detector to replace LTCC Project under development

  20. + K+ - K- epe’K+X • K+ ampl. >p+ampl. • Unespected from u-quark dominance! • How large can the effect of s quarks be? S.Arnold et al. 0805.2137 /K measurement @ CLAS12 will provide a more detailed knowledge of Sivers effect M. Anselmino et al. 0805.2677 Kaon TMDs program @ 12 GeV in Hall B HERMES coll. PRL 103 (2009)

  21. Measurements of azimuthal dependences of single and double spin asymmetries indicate that correlations between spin and transverse motion of quarks may be significant • CLAS in Hall B at Jlab is playing a major role in these studies • The new CLAS experiment with longitudinally polarized NH3 and ND3 targets provides superior sample of events allowing multidimensional binning to study: • - SSAs for  and  in SIDIS • - Higher Twists and quark-gluon correlations • - Double spin asymmetries and flavor decomposition of helicity dist. • Studies of the spin-structure of the nucleon is one of the main driving forces behind the upgrade of Jefferson Lab • JLab12 with wide kinematic coverage, high luminosity, high polarization is essential for high precision measurements of 3D PDFs in the valence region Conclusions and Outlook

More Related