P. Rossi Laboratori Nazionali di Frascati - INFN IFAE2011 Incontri di Fisica delle Alte Energie Perugia April 27-29, 2011 The Jefferson Laboratory A glance to the program at 12 GeV - Nucleon Form Factors - Nucleon Tomography - Meson Spectroscopy & Search for Exotics Conclusions

A B C CEBAF Energy :0.8 ─ 6 GeV Duty factor:100%(CW beam) Beam Polarization:75-85% Beam to 3 Halls simultaneously with Independent Variable Energy and Intensity Luminosity: cm -2 s -1 Distance Energy heavy nuclei few body quarks gluons vacuum A laboratory from “strong” to perturbative QCD

12 GeV Upgrade  Enhanced capabilities in existing Halls  Increase of Luminosity ~10 39 cm -2 s -1 New Hall CHL-2 Maintain capability to deliver lower pass beam energies May GeV Accelerator Shutdown starts May 2013 Accelerator Commissioning starts October 2013 Hall Commissioning starts

JLab Physics 12 GeV Hall A – form factors, SRC, GPDs & TMDs, Low-energy tests of the SM and Fund. Symmetry Exp. Hall C – precision determination of valence quark properties in nucleons and nuclei Hall B - understanding 3-D nucleon structure via GPDs & TMDs - Search of new form of hadronic matter via Meson Spectroscopy Hall D - exploring origin of confinement by studying exotic mesons using real photons high momentum spectrometers, dedicated equipments 4  – superior PID high luminosity, high resolution & dedicated equipments high energy real photon

JLab Physics 12 GeV Hall A – form factors, SRC, GPDs & TMDs, Low-energy tests of the SM and Fund. Symmetry Exp. Hall C – precision determination of valence quark properties in nucleons and nuclei Hall B - understanding 3-D nucleon structure via GPDs & TMDs - Search of new form of hadronic matter via Meson Spectroscopy Hall D - exploring origin of confinement by studying exotic mesons using real photons high momentum spectrometers, dedicated equipments 4  – superior PID high luminosity, high resolution & dedicated equipments high energy real photon

Nucleon Form Factors Jones et al., PRL 84, 1398 (2000)- Punjabi et al., PRC 71, (2005) Gayou et al., PRL 88, (2002) Puckett et al., PRL 104: (2010) Andivahis et al., PRD 50, 5491 (1994) Christy et a., PRC 70, (2004) Quattan et al., PRL 94, (2005) OPE assumption used in the Rosenbluth separation spatial distributions electric charge current spatial distributions of electric charge and current

Nucleon Form Factors Jones et al., PRL 84, 1398 (2000)- Punjabi et al., PRC 71, (2005) Gayou et al., PRL 88, (2002) Puckett et al., PRL 104: (2010) Andivahis et al., PRD 50, 5491 (1994) Christy et a., PRC 70, (2004) Quattan et al., PRL 94, (2005) OPE assumption used in the Rosenbluth separation Polarization transfer technique gives different results! spatial distributions electric charge current spatial distributions of electric charge and current

Nucleon Form Factors Jones et al., PRL 84, 1398 (2000)- Punjabi et al., PRC 71, (2005) Gayou et al., PRL 88, (2002) Puckett et al., PRL 104: (2010) Andivahis et al., PRD 50, 5491 (1994) Christy et a., PRC 70, (2004) Quattan et al., PRL 94, (2005) OPE assumption used in the Rosenbluth separation Polarization transfer technique gives different results! REVOLUTIONAZED OUR KNOWLEDGE OF CHARGE AND CURRENT IN THE NUCLEON Double polarization experiments only possible with high intensity, high polarized beam spatial distributions electric charge current spatial distributions of electric charge and current

Nucleon Form Factors 12 GeV Tests for phenomenological models Study of transition region between the perturbative and non-perturbative QCD description Constraint of the GPDs H and E High Q 2 measurements:

3D Nucleon Structure Frontier byby b x 3-D Scotty x 2-D Scotty x byby 10 1-D Scotty x probablity Calcium Water Carbon Courtesy of V. Burkert

3D Nucleon Structure Frontier byby b x 3-D Scotty x 2-D Scotty x byby 11 1-D Scotty x probablity Calcium Water Carbon Deep Inelastic Scattering & Forward Parton Distribution Functions. Courtesy of V. Burkert

3D Nucleon Structure Frontier byby b x 3-D Scotty x Deeply Virtual Processes. GPDs & TMDs 2-D Scotty x byby 12 1-D Scotty x probablity Calcium Water Carbon Deep Inelastic Scattering & Forward Parton Distribution Functions. Courtesy of V. Burkert

The 3-D Picture of the Nucleon Proton form factors Proton form factors transverse charge & current densities Structure functions quark longitudinal momentum & helicity distributions

The 3-D Picture of the Nucleon Proton form factors Proton form factors transverse charge & current densities Structure functions quark longitudinal momentum & helicity distributions Generalized Parton Distributions Correlated distributions in transverse space + = GPD(x, ,t) x+  x-  p p’ t GPDs are generalization of PDFs when one allows: - momentum transfer to the nucleon - longitudinal momentum transfer to the quark They represent interference of amplitudes  NO probabilistic interpretation x : longitudinal quark momentum fraction  : longitudinal quark momentum transfer t : momentum transfer to the target xB xB 2-x B  =

Accessing GPDs Deeply Virtual Compton Scattering (DVCS) Deeply Virtual Meson Production (DVMP) MeasurementsinEXCLUSIVE reactions Measurements in EXCLUSIVE reactions ~ H E VM (   H E H E PS mesons (  : H E H, E, H, E DVCS (  ): H, E, H, E~~ ~ By doing Fourier transform, they give longitudinal momentum distributions of quark at a given transverse point in the nucleon  3D imaging of the nucleon Quantum number of final state selects different GPDs:

Extracting GPDs: experimental requests Difficult to extract GPDs from the data GPDs calculations possible ONLY through models/parameterizations Physical observables involve convolution of GPDs - only  and t accessible exp. GPDs are more complicated than PDFs - functions of 3 variables instead of 1 Exclusive reactions are smaller and harder to measure than inclusive ones high+variable beam energy (hard regime, wide kinematic range) high luminosity (small cross sections, measure>1 kinematic variables simultaneously ) complete event reconstruction (ensure exclusivity)

Extracting GPDs: experimental requests Difficult to extract GPDs from the data GPDs calculations possible ONLY through models/parameterizations Physical observables involve convolution of GPDs - only  and t accessible exp. GPDs are more complicated than PDFs - functions of 3 variables instead of 1 Exclusive reactions are smaller and harder to measure than inclusive ones high+variable beam energy (hard regime, wide kinematic range) high luminosity (small cross sections, measure>1 kinematic variables simultaneously ) complete event reconstruction (ensure exclusivity) Beam Spin Asymmetry PR DVCS in Hall B at 12 GeV

Extracting GPDs: experimental requests Difficult to extract GPDs from the data GPDs calculations possible ONLY through models/parameterizations Physical observables involve convolution of GPDs - only  and t accessible exp. GPDs are more complicated than PDFs - functions of 3 variables instead of 1 Exclusive reactions are smaller and harder to measure than inclusive ones high+variable beam energy (hard regime, wide kinematic range) high luminosity (small cross sections, measure>1 kinematic variables simultaneously ) complete event reconstruction (ensure exclusivity) Beam Spin Asymmetry PR DVCS in Hall B at 12 GeV  LU  ~ sin  {F 1 H + ξ (F 1 +F 2 ) H +kF 2 E }d  LU  ~ sin  {F 1 H + ξ (F 1 +F 2 ) H +kF 2 E }d  ~ ~ H(ξ,t) Kinematically suppressed

Nucleon 3-D Picture in Momentum Space Nucleon spin as probed in DIS is incomplete!  0.3 small could be large The orbital motion of quarks and gluons and spin-orbit correlations can be described by transverse momentum dependent (TMD) parton distribution functions Moments of ,  s SIDIS measurements

Transverse Momentum Dependent Distributions Quark polarization Nucleon polarization Boer-Mulders pretzelosity transversity Sivers worm gear worm-gear helicity L f 1 =f 1 (x,k ) T TMDs probe the quarks’ orbital motion. Complete program of TMDs studies for pions and kaons

Transverse Momentum Dependent Distributions Quark polarization Nucleon polarization Boer-Mulders pretzelosity transversity Sivers worm gear worm-gear helicity L f 1 =f 1 (x,k ) T TMDs probe the quarks’ orbital motion. Collins Complete program of TMDs studies for pions and kaons

The Nucleon Parton Model In the collinear approximation PDF

The Nucleon Parton Model TMDs Parton transverse momentum Light-cone quark model calculation, Boffi et al. In the collinear approximation PDF

Asimmetry with a Longitudinally pol. Targ. in Hall B Ph. Haegler et al arXiv:

Gluonic Excitations and the Origin of Confinement QCD predicts a rich spectrum of - as yet to be discovered - gluonic excitations whose experimental verification is crucial for an understanding of QCD in the confinement regime J pc = q q q q Lattice GeV GeV GeV Exotic J PC are more likely produced by S=1 probe photoproduction Exotic J PC are more likely produced by S=1 probe  photoproduction Experimental Halls dedicated to this program: Hall D and Hall B

Meson Spectroscopy in Hall B

Tagger (E  ) : required to add 'production' information to decay Linear polarization: useful to simplify the PWA analysis High intensity High energy (5-9 GeV) The photon beam

Meson Spectroscopy in Hall B Tagger (E  ) : required to add 'production' information to decay Linear polarization: useful to simplify the PWA analysis High intensity High energy (5-9 GeV) The photon beam Use quasi-real photo-production with detection of scattered electrons at “0” degrees (2.5° - 4.5°) with a FORWARD TAGGER The technique 50 cm

Meson Spectroscopy in Hall B Tagger (E  ) : required to add 'production' information to decay Linear polarization: useful to simplify the PWA analysis High intensity High energy (5-9 GeV) The photon beam Use quasi-real photo-production with detection of scattered electrons at “0” degrees (2.5° - 4.5°) with a FORWARD TAGGER The technique Coherent tagged Brems. (HALL D)  quasi-real (HALL B) E  (GeV) L (cm- 2 s- 1 ) 5x10 31 Polarization40% (average) 70%-10% (event-by-event) Acceptance (3  ) 90%20% Hadron  p/p 2%0.5% Hadron PIDNo K id/kin fit K/  separation 50 cm

The Italian JLAB12 Collaboration Sezione di Alessandria Sezione di Bari Sezione di Cagliari Sezione di Catania Sezione di Ferrara Sezione di Genova Istituto Superiore di Sanità Laboratori Nazionali di Frascati Sezione di Milano Bicocca Sezione di Pavia Sezione di Perugia Sezione di Pisa Sezione di Roma I Sezione di Roma II Sezione di Torino Sezione di Trento The Italian Collaboration includes 80 scientists among experimentalists (~45) and theorists from 16 INFN Units and National Laboratories, who are participating to the 6 GeV running and 12 GeV Upgrade

Conclusions The JLab Upgrade at 12 GeV has well defined physics goals of fundamental importance for the future of hadron physics, addressing in new and revolutionary ways the quark and gluon structure of hadrons by The JLab Upgrade at 12 GeV has well defined physics goals of fundamental importance for the future of hadron physics, addressing in new and revolutionary ways the quark and gluon structure of hadrons by Accessing GPDs and TMDs for a 3-D description of the nucleonAccessing GPDs and TMDs for a 3-D description of the nucleon Mapping the valence quark structure of nucleons with high precisionMapping the valence quark structure of nucleons with high precision Exploring the physical origins of quark confinementExploring the physical origins of quark confinement Extending nucleon form factors to short distancesExtending nucleon form factors to short distances Probing potential new physics through high precision tests of the Standard ModelProbing potential new physics through high precision tests of the Standard Model Accelerator and equipment upgrades are underway Accelerator and equipment upgrades are underway Accelerator commissioning scheduled for 2013 Accelerator commissioning scheduled for 2013

Backup slides

HallproposalEnergyprocesspol. beam/target BPR DVCSUL,LU beam and target spin asymmetry APR ,8.8, 11 DVCSUU,LU Helicity-dependent cross sections BLOI DVCSUTtarget spin asymmetry BPR DVMP  0,  UU,LU L/T separation, cross section, beam spin asym. CPR DVMP  + UUL/T separation BLOI hyperons K+ , K*+   polarization green: approved proposals blue: Letter of Intent to be developed in full proposal The GPDs program at GeV

x B =0.24 Beam Spin Asymmetry TARGET Spin Asymmetry Projected data 80 days at L =10 35 cm -2 s days at L =2 ·10 35 cm -2 s -1 PR DVCS in Hall B at 12 GeV

H1, ZEUS JLab Upgrade 11 GeV H1, ZEUS 12 GeV 11 GeV 27 GeV 200 GeV W = 2 GeV Study of high x B domain requires high luminosity 0.7 HERMES COMPASS The 12 GeV Upgrade is well matched to studies in the valence quark regime.