TRAN poster xin test

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Collins effect ( Sin(φh+ φS) ) Access to transversity Artru model Based on LUND fragmentation picture. Neutron (e,e’π±) Target Single-Spin Asymmetry in Semi-inclusive DIS on a Transversely Polarized 3He Target Kalyan Allada, Chiranjib Dutta, Mitra Shabestari, Xin Qian On the behalf of Transversity Collaboration Two experiments with the highest scientific rate: Nucleon Structure Nucleon anomalous magnetic moment (Stern, Nobel Prize 1943) Electromagnetic form factor from electron scattering (Hofstadter, Nobel Prize 1961) Deep-in-elastic scattering, quark underlying structure of the nucleon (Freedman, Kendell, Taylor, Nobel Prize 1990) Understanding the underlying nucleon structure (Spin, flavor, charge, current distribution) from quantum chromodynamics (confinement region) is essential. Electronuclear Scattering ------ A powerful tool to study nuclear structure Inclusive: (the main tool) detecting electron only Semi-inclusive: (providing additional information) detecting electron and one of the hadrons coincidently Spectrum: What is Semi-Inclusive Deep Inelastic Scattering (SIDIS) E’ is the energy of scattered electron θe is the scattering angle ν =E-E’ is the energy transfer. kT: quark transverse momentum Characteristics of Transversity Some characteristics of transversity : h1T = g1L for non-relativistic quarks In non-relativistic case, boosts and rotations commute. Important inequalities: |h1Tq| ≤ f1q ; |h1Tq| ≤ (f1q + g1Lq )/2. h1T and gluons do not mix Q2-evolution for h1T and g1L are different Chiral-odd → not accessible in inclusive DIS N q q N Helicity state - + It takes two Chiral-odd objects to measure transversity Drell-Yan (Doubly transversely polarized p-p collision) Semi-inclusive DIS Chiral-odd distributions function (transversity) Chiral-odd fragmentation function (Collins function) - Detector system & 3He Target HRS HALL-A 3He Target Projections HRS Collins and Sivers Asymmetry Parton distribution Function (PDF) Fragmentation function (FF) DXs~PDF*FF The kinematics and coordinate DIS: Q2 (1/λ) and ν is large, but x is finite. Scattering plane Beam direction Into the page Sivers effect ( Sin(φh- φS) ) A new type of PDF, T-odd, depends on intrinsically quark transverse momentum quark orbital momentum Asymmetry in Semi-Inclusive DIS with polarized target 40-cm long Rb-K spin-exchange hybrid cell at 10 atm . ~42% target polarization with spin-flip frequency of 20 minutes. A third set of Helmholtz coil will be added together with the laser optics to allow vertical polarization of the 3He target. Target Polarimetry NMR and EPR will be used to measure the target polarization. First direct data on neutron AUT At high-x Clear separation of Collins and Sivers effect. Statistical uncertainty dominates. Kinematics comparable to the HERMES experiment. Hall-A Setup Beam - 6Gev, 15 microA electron beam Target Electron detection - BigBite spectrometer, solid angle = 64msr, at 300 Charged pion detection - Hall-A High Resolution Spectrometer, at -160 Transversity, business just started. HALL A: 29 days HERMES: 3 years COMPASS: 1 year Well Known, since first measurement at 70s. Reasonable Known with 20 years effort. A