Franco Bradamante CSN1, Trieste, 18 settembre 2006

F. BradamanteCSN1, 18 settembre 2006 STATO DELL’ESPERIMENTO

F. BradamanteCSN1, 18 settembre 2006

F. BradamanteCSN1, 18 settembre 2006

F. BradamanteCSN1, 18 settembre 2006

F. BradamanteCSN1, 18 settembre 2006 PROGETTI INFN ne parlo dopo

F. BradamanteCSN1, 18 settembre 2006

F. BradamanteCSN1, 18 settembre 2006

F. BradamanteCSN1, 18 settembre 2006 UPGRADE DEL RICH

F. BradamanteCSN1, 18 settembre 2006 SPSC e FRC Stato dell’esperimento e del run 2006 presentato da A. Magnon il 1 settembre 2006 all’FRC

F. BradamanteCSN1, 18 settembre 2006 Run luglio: dopo i problemi con i compensatori del PS e del SPS, inizio setting up del fascio nella North Area: problemi nel trasporto del fascio lungo la linea luglio: scrubbing run. Problemi della linea di fascio identificati e risolti. 24 luglio, sera: primo fascio nella zona sperimentale, con intensita’ molto bassa (1-3·10 11 ). 29 luglio: black out al CERN, con arresto degli acceleratori fino al 1 agosto 1 agosto: restart degli acceleratori. Problemi con il septum del PS (poi sostituito) 7 agosto, sera: primo fascio nella zona; intensita’ ragionevole dal 10 agosto. Proseguimento commissioning: dal 14 agosto problema con trasparenza radiatore (completamente trasparente il 28 agosto) 17/18 agosto: calibrazione ECAL con elettroni completata problemi vari con la temporizzazione di diversi rivelatori … inizio presa dati: questa settimana (incontro con i referee del 1/9…)

F. BradamanteCSN1, 18 settembre 2006 Very promising results ! - Precise timing - High photon statistics UPGRADE DEL RICH – MAPMT on-line display

F. BradamanteCSN1, 18 settembre 2006 Stato dell’esperimento

F. BradamanteCSN1, 18 settembre 2006 RISULTATI di FISICA  muon beam, longitudinal target polarisation:  ΔG/G open charm  ΔG/G high-p T ( : PLB 633 (2006) )  A 1 d and QCD fits (Q 2 >1: inviato per pubblicazione)  Hard exclusive ρ 0 production  Λ polarisation  muon beam, transverse target polarisation:  Transversity and Sivers (Nucl. Phys. READY)  Transversity and Sivers π ± and K ±  Transversity from 2-hadron pairs  Transversity from Λ transverse-polarisation (SPIN2006)  hadron beam:  primakoff scattering 4 papers published

F. BradamanteCSN1, 18 settembre 2006 A 1 d e fit di QCD

F. BradamanteCSN1, 18 settembre 2006 A 1 d e fit di QCD

F. BradamanteCSN1, 18 settembre 2006 A 1 d e fit di QCD

F. BradamanteCSN1, 18 settembre 2006 A 1 d e fit di QCD

F. BradamanteCSN1, 18 settembre 2006 A 1 d e fit di QCD

F. BradamanteCSN1, 18 settembre 2006 A 1 d e fit di QCD

F. BradamanteCSN1, 18 settembre 2006 A 1 d e fit di QCD

F. BradamanteCSN1, 18 settembre 2006 A 1 d e fit di QCD

F. BradamanteCSN1, 18 settembre 2006 GRSV2000 NLO fits to g 1 μ 2 = 3 Gev 2 ΔG/G (x g ≈ 0.1) is small ΔG>1 disfavoured MISURA DIRETTA DI ΔG/G ∫  G(x) = 2. 5 ∫  G(x) = 0.6 ∫  G(x) = 0.2 Consistent also with RHIC A LL (π 0 channel) measurements

F. BradamanteCSN1, 18 settembre 2006 RHIC Run6 Expectations Higher polarization (~60%) and luminosity have been achieved in Run06. This will decrease our uncertainty by a factor of ~4 (~3 when all Run5 data is considered).

F. BradamanteCSN1, 18 settembre 2006 RISULTATI DI FISICA muon beam, transverse target polarisation:  Transversity and Sivers Nucl. Phys. READY 2002: PRL 94 (2005)  Transversity and Sivers π ± and K ±  Transversity from 2-hadron pairs  Transversity from Λ transverse-polarisation SPIN2006

F. BradamanteCSN1, 18 settembre 2006 Collins Asymmetries 2002 vs risultati released da dati (DIS2006) confronto con i dati 2002 pubblicati PRL 94 (2005)

F. BradamanteCSN1, 18 settembre 2006 DIS2006 Collins Asymmetries small errors (~1%) small asymmetries cancellation between p and n (lh and ah)

F. BradamanteCSN1, 18 settembre 2006 DIS2006 Sivers Asymmetries small errors (~1%) small asymmetries cancellation between p and n (lh and ah)

F. BradamanteCSN1, 18 settembre 2006 Collins Asymmetries RICH PID NEW!

F. BradamanteCSN1, 18 settembre 2006 Sivers Asymmetries RICH PID NEW!

F. BradamanteCSN1, 18 settembre 2006 Coppie di adroni nella produzione di coppie di adroni si puo’ definire un diverso angolo ► misurare un’asimmetria diversa  R angolo azimutale di R ┴  s’ =  s angolo azimutale dello spin del quark che frammenta  RS =  R -  s’ A. Bacchetta, M. Radici, hep-ph/ ; X. Artru, hep-ph/

F. BradamanteCSN1, 18 settembre 2006 different hadron pairs selections have been tried (still based on the string fragmentation model) 1.h1 = +ve hadron largest p T h2 = -ve hadron with second largest p T and h1 = -ve hadron largest p T h2 = +ve hadron with second largest p T 2.h1 = +ve hadron largest z h2 = -ve hadron with second largest z and h1 = -ve hadron largest z h2 = +ve hadron with second largest z plus equal charge combinations 6.4 M events Two Hadron Asymmetries SPIN 2005 CIPANP06 1 entry/event

F. BradamanteCSN1, 18 settembre 2006 Two Hadron Asymmetries all hadron pairs CIPANP 06 DIS2005 NEW

F. BradamanteCSN1, 18 settembre 2006 “Where is the proton’s spin ?” question of F. Close, Physics World 1989 Ji sum rule helicity sum rule transverse spin sum rule transversity can be a short-cut no  G L q and L g can be obtained from Sivers effect transverse L q,g ↔ longitudinal L q,g being investigated precise determination impossible with present experiments comment by R. Jaffe at QCD-N’02

F. BradamanteCSN1, 18 settembre 2006 Importanza degli Effetti di SPIN Trasverso large spin effects known in hadron physics at high energy since many years see G. Bunce at Transversity 2005, Como (Italy) 7-10 September 2005 important theoretical work in QCD transversity distribution function and ways to measure it Collins effect Sivers effect literally an EXPLOSION over the past 5 years TMD FF and PDF nowadays GPDs

F. BradamanteCSN1, 18 settembre 2006 da G. BUNCE Transversity 2005 Villa Olmo (Como) 7−10 th September 2005

F. BradamanteCSN1, 18 settembre 2006 q(x)  q(x)  T q(x) momentum distribution helicity distribution transversity distribution TRANSVERSE SPIN PHYSICS 3 distribution functions are necessary to describe the structure of the nucleon at LO: all of equal importance !  T q (x) decouples from leading twist DIS because helicity of quark must flip NO MIXTURE WITH GLUON

F. BradamanteCSN1, 18 settembre 2006 Asimmetria di Collins  T q(x) e’ chirally-odd effetto Collins funzione di frammentazione dipendente dallo spin del quark un quark con spin verso l’alto emette preferenzialmente l’adrone leading a destra nel jet k h s

F. BradamanteCSN1, 18 settembre 2006 Asimmetria di Collins h s   C =  h -  s’ =  h +  S -π

F. BradamanteCSN1, 18 settembre 2006 Asimmetria di Sivers due ingredienti: 1. interazioni di stato finale la QCD ci dice che le FSI devono essere attrattive perche’ il quark e i quark spettatori formano uno stato antisimmetrico di colore top front “lente cromodinamica” z y z x x x x y

F. BradamanteCSN1, 18 settembre 2006 Asimmetria di Sivers 2. PDF di Sivers la presenza dello spin trasverso del nucleone puo’ distorcere la distribuzione dei quark nello spazio trasverso e’ necessario il momento angolare front distribuzione di Sivers assieme a FSI ▼ asimmetria azimutale di Sivers top z y z x x x x y

F. BradamanteCSN1, 18 settembre 2006 Asimmetria di Sivers   C =  h -  s’ =  h +  S -π SSSS   S =  h -  S

F. BradamanteCSN1, 18 settembre 2006 Collins and Sivers asymmetries calculated as function of x, z and p t for Leading Hadrons and All Hadrons

F. BradamanteCSN1, 18 settembre 2006 Transverse Spin Effects The facts: HERMES has measured on a proton target non-zero SSA for π + and π - Collins effect: ► both Δ T q transversity distribution and Δ T 0 D Collins FF are NON-ZERO BELLE has produced the first results on spin-dependent FF ► non-zero Collins FF Conclusion: Collins mechanism is a real phenomenon universality of Collins mechanism transversity can be measured in SIDIS

Measurement of the Collins fragmentation function at BELLE QCDN06, June 14 th Collins fragmentation in e + e - : Angles and Cross section cos(     ) method       2-hadron inclusive transverse momentum dependent cross section: Net (anti-)alignment of transverse quark spins  e + e - CMS frame: e-e- e+e+ [D.Boer: PhD thesis(1998)]

Measurement of the Collins fragmentation function at BELLE QCDN06, June 14 th Results for e + e -   X for 29fb -1 Significant non-zero asymmetries Rising behavior vs. z cos      double ratios only marginally larger First direct measurement of the Collins function Integrated results: –cos(2   ) method (3.06±0.57±0.55)% –cos(2     ) method (4.26±0.68±0.68)% z1z1 z2z2 Systematic error A0A0 A 12 Final results

F. BradamanteCSN1, 18 settembre 2006 Transverse Spin Effects More facts: HERMES has measured on a proton target non-zero Sivers effect for π + ► also Sivers mechanism is a real phenomenon important theoretical work to connect Sivers SSA with L q and E COMPASS has measured on a deuteron target ~ 0 Collins and Sivers asymmetries ► first and unique handle on  T d before JLAB(?), no way in Drell-Yan ► first and unique handle on Lg

F. BradamanteCSN1, 18 settembre 2006 E GPD and Sivers effect talk by M. Burkardt at QCD-N’06 (Frascati, June 12-16, 2006) also claimed by HERMES (talk by G. Schnell at QCD-N’06)

F. BradamanteCSN1, 18 settembre 2006 a close look at HERMES and COMPASS data

F. BradamanteCSN1, 18 settembre 2006 COMPASS preliminary NEW! deuteron HERMES DIS2006 proton Pion Asymmetries

F. BradamanteCSN1, 18 settembre 2006 A lot of theoretical work on COMPASS 2002 published data and the HERMES data Presently, our deuteron data on COLLINS SSA can be interpreted only in a combined analysis which uses PROTON DATA, while our SIVERS SSA alone tell that  0 T u ~ -  0 T d All model calculations fit HERMES data some fit also 2002 COMPASS data and/or BELLE data To extract TMD DF and FF GLOBAL ANALISYS are necessary (many groups have already started)

F. BradamanteCSN1, 18 settembre 2006 Comparison with Models 1 comparison of some model calculations with our NEW data Vogelsang and Yuan, 2005 the (published) comparison with the 2002 data was good PRELIMINARY

F. BradamanteCSN1, 18 settembre 2006 Comparison with Models 2 Efremov et al., 2006 Efremov et al., 2005 the (published) comparison with the 2002 data was good PRELIMINARY

F. BradamanteCSN1, 18 settembre 2006 Comparison with Models 3 Anselmino et al., 2006 Anselmino et al., 2005 the (published) comparison with the 2002 data was good PRELIMINARY

F. BradamanteCSN1, 18 settembre 2006 Comparison with Models conclusion all the models could reproduce at the same time the HERMES and the COMPASS 2002 data present general picture Collins: u quark dominance (d ~unconstrained)  T 0 D(fav.) ~ -  T 0 D(unfav) for u quark Sivers:  0 T u ~ -  0 T d the same models need retuning to reproduce the new COMPASS data confirmation of the present picture? first extraction of d quark transversity?

F. BradamanteCSN1, 18 settembre 2006 To conclude Transversity in its various manifestations is a newly discovered property of matter Precise proton data at COMPASS energy are necessary and eagerly waited for in the scientific community Vogelsang and Yuan, Phys.Rev.D72:054028,2005 …. The COMPASS result on the deuteron target is an important result HIGHLY NON-TRIVIAL J. Collins at “Workshop on the Helicity Structure of the Proton”, BNL, June 5-9, 2006 S. Brodsky in hep-ph/ …

F. BradamanteCSN1, 18 settembre 2006 The most recent PRL citation Due to the smallness of the anomalous magnetic moment of the nucleon the orbital motion of the quarks should not contribute to the Sivers SSA of the deuteron. Thus 2002 data Evidence for the Absence of Gluon Orbital Angular Momentum in the Nucleon S.J. Brodsky, S. Gardner SLAC-PUB-12062, Aug Subm. Phys.Lett.B, hep-ph/