Скачать презентацию SNAPMOC S REC TA PION POLARIZABILITY Murray Moinester Скачать презентацию SNAPMOC S REC TA PION POLARIZABILITY Murray Moinester

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SNAPMOC S REC TA PION POLARIZABILITY Murray Moinester Tel Aviv University Institute of Nuclear SNAPMOC S REC TA PION POLARIZABILITY Murray Moinester Tel Aviv University Institute of Nuclear Theory, University of Washington, August 2012

The polarizabilities [in 10 -4 fm 3] The polarizability (electric and magnetic ) relates The polarizabilities [in 10 -4 fm 3] The polarizability (electric and magnetic ) relates the average dipole (electric p and magnetic ) moment to an external electromagnetic field, characterizing the rigidity of the quark-antiquark system The pion polarizabilities can be described in the framework of the Chiral Perturbation Theory ( PT) based on the chiral symmetry of QCD and Goldstone theorem using the effective chiral lagrangian The numerical values are: (απ+βπ)= 0. 16; (απ-βπ)=(5. 7± 1. 0) [1] Other models (dispersion sum rules[2], QCD sum rule[3], lattice calculations[4], …) predict quite different value for the pion polarizabilities : 0<(απ+βπ)<0. 39; 3. 2<(απ-βπ)<11. 2 [5] [1] J. Gasser et al. , Nucl. Phys B 745 (2006) 84 -108 [2] L. V. Fil’kov et al. , Eur. Phys. J. A 5 (1999) 285 [3] M. J. Lavelle et al. , Phys. Lett. B 335 (1994) 211 [4] W. Wilcox. , Phys. Rev D 57 (1998) 6731 [5] A. Wilmot et al. , Phys. Rev. C 65 (2002) 035206

The Primakoff reaction + Z ’ + Z + ’ Inverse kinematics for the The Primakoff reaction + Z ’ + Z + ’ Inverse kinematics for the Compton scattering: γ*π→γπ’ In the incoming pion rest frame (Anti-laboratory system) γ γ* Z, A απ, βπ independently ω is the energy of the virtual photon in the anti-laboratory sys. Assuming (απ+βπ)= 0 in the Laboratory system: βπ Q 2 max depends on analysis cut Eγ is the energy of the real photon

Experimental values Experiment Reaction [10 -4 fm 3] Lebedev γp→γπ+n 20± 12 PLUTO γγ→π+π- Experimental values Experiment Reaction [10 -4 fm 3] Lebedev γp→γπ+n 20± 12 PLUTO γγ→π+π- 19. 1± 4. 8± 5. 7 DM 1 γγ→π+π 17. 2± 4. 6 DM 2 γγ→π+π 26. 3± 7. 4 MARK II γγ→π+π 2. 2± 1. 6 Serpukhov πZ→πZγ 6. 8 ± 1. 4± 1. 2 Experiment Reaction ( +β)[10 -4 fm 3] Serpukhov πZ→πZγ 1. 4± 3. 1± 2. 8 Experiment Reaction ( -β) [10 -4 fm 3] Serpukhov πZ→πZγ 13. 6 ± 2. 8 MAMI-A 2 γp→γπ+n 11. 6± 1. 5± 3. 0± 0. 5 The experiments are affected by too large statistical and/or systematic errors

COMPASS NA 58 experiment at CERN SPS COmmon Muon and Proton Apparatus for Structure COMPASS NA 58 experiment at CERN SPS COmmon Muon and Proton Apparatus for Structure and Spectroscopy 20 Institutes/11 counties/~230 physicists Czech Republic, Finland, France, Germany, India, Israel, Italy, Japan, Poland, Portugal and Russia Bielefeld, Bochum, Bonn, Burdwan/Calcutta, CERN, Dubna, Erlangen, Freiburg, Lisbon, Mainz, Moscow, Munich, Prage, Protvino, Saclay, Tel Aviv, Torino, Trieste, Warsaw and Yamagata

COMPASS  at CERN Lake LEMAN COMPASS Airport SPS LHC CERN (France) N CERN (Suisse) COMPASS  at CERN Lake LEMAN COMPASS Airport SPS LHC CERN (France) N CERN (Suisse) • p up to 400 Ge. V 16/03/2018 BEACH 08 • secondary hadrons ( , K, . . . ): 2· 107/s 26 june 2008 19 • tertiary (polarized): 4· 107/s. New Frontiers in QCD, February 5, 2010 Takahiro Iwata

Trigger Experimental conditions during the 2004 hadron run (7 days) • Beam: 190 Ge. Trigger Experimental conditions during the 2004 hadron run (7 days) • Beam: 190 Ge. V/c; ~106 π/s, 4. 8 s / 16 s spill structure Beam 190 Ge. V/c; ~108 μ/s • Targets: 1. 6 – (2+1) - 3 mm Pb , 7 mm Cu, 23 mm C Targets • Triggers: • Primakoff 1 = Hodoscope hit x ECal 2 (E>50 Ge. V) x HCal 2 (E>18 Ge. V) • Primakoff 2 = ECal 2 (E>100 Ge. V) • Saturated trigger rate (40 -50 k/spill)

THE RICH DETECTOR 3 m 6 m 5 m photon detectors C 4 F THE RICH DETECTOR 3 m 6 m 5 m photon detectors C 4 F 10 • radiator gas: C 4 F 10 20 m 2 surface • mirror wall: • photon-detectors: • outer part (75%) MWPC(pad RO) with Cs. I cathode • inner part(25%) 576 MAPMTs with indiv. telescope threshold momenta ● p = 2 Ge. V/c ● p = 9 Ge. V/c K ● p =17 Ge. V/c P Installed in 2005, Used in data taking from 2006

The Compass Spectrometer The Compass Spectrometer