HADRON SPECTROSCOPY AT COMPASS Exotic Hadrons at COMPASS

HADRON　 SPECTROSCOPY AT COMPASS -- Exotic Hadrons at COMPASS -Takahiro Iwata Yamagata University on behalf of the COMPASS Collaboration New Frontiers in QCD, February 5, 2010

OUTLINE § Introduction to COMPASS § Physics in Hadron Spectroscopy § Diffractive dissociation to p-p-p+ § Diffractive dissociation to p-p 0 p 0 § Central production of 4 -charged-pions § p-h, p-hh channels § Kaonic final states: KKp, KK, Kp § Conclusion Takahiro Iwata New Frontiers in QCD, February 5, 2010

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 Takahiro Iwata New Frontiers in QCD, February 5, 2010

COMPASS 　at CERN Lake LEMAN COMPASS Airport LHC SPS CERN (France) N CERN (Suisse) 09/09/2020 Takahiro Iwata BEACH 08 26 june 2008 4 New Frontiers in QCD, February 5, 2010

PHYSICS PROGRAMS OF COMPASS • Muon program pol-m beam: Runs: 2002 -04, 06 -07 Nucleon Spin Structure • Gluon polarization DG/G • g 1 spin structure function • Flavor decomposition of spin distributions • Transverse spin effects • Spin transfer in Lhyperon production • Vector meson production Takahiro Iwata • Hadron program hadorn-beams: Runs : 2004, 08 -09 Hadron spectroscopy • Diffractive production • Search for new exotic states, glueballs or hybrids • Light meson spectroscopy Primakov scattering • Polarizabilities （Doubly charmed baryons） New Frontiers in QCD, February 5, 2010

SETUP FOR MUON PROGRAM An experiment with pol. muon beam and pol. target at CERN two stages spectrometer • Large Angle Spectrometer (SM 1) • Small Angle Spectrometer (SM 2) tracking, calorimetry, PID(RICH/muon-filter) High rate capability Sci. Fi Straws Silicon Micromegas SDC MWPC E/HCAL GEMs W 45 SM 1 Polarized Target Pol. m beam 160 Ge. V/c Pol. 80% ｆrom SPS (CERN) Takahiro Iwata Muon. Wall SM 2 E/HCAL 0. 003 < x < 0. 5 10 -3 < Q 2 < 10 Ge. V 2 Muon. Wall RICH • high energy beam • broad kinematical range • large angular acceptance NIM A 577(2007) 455 New Frontiers in QCD, February 5, 2010

SETUP FOR HADRON PROGRAM Target: liquid H 2, 40 cm long (Pb in 2004 pilot run) 2008 -09 Beam: 190 Ge. V positive/negative hadrons Negative: 96% -, 3. 5% K-, 0. 5% p-bar Positive: 75% p, 25% +, 5% K+ Beam intensity: 2· 107/s ( 108/spill, spill=4. 8 s, cycle=16. 8 s) P-id by beam Cherenkov Counter (CEDAR) Takahiro Iwata New Frontiers in QCD, February 5, 2010

TARGET PART IN HADRON PROGRAM RPD(Recoil Proton Detector) Installed in 2007 Takahiro Iwata New Frontiers in QCD, February 5, 2010

Physics in Hadron Spectroscopy Takahiro Iwata New Frontiers in QCD, February 5, 2010

PHYSICS GOALS • Objectives mainly in meson spectroscopy • QCD allows states which are forbidden in the quark Model • Exotic states • Glueballs: • Hybrids : • Tetraquarks : • Mixing with ordinary mesons with the same quantum numbers complicated situation • Exotic JPC states : non-qq states : important to find them COMPASS contributes in the low mass region Takahiro Iwata New Frontiers in QCD, February 5, 2010

GLUEBALLS Quenched L-QCD prediction Lightest glueballs: 　　scalar tensor Experimental candidate: • f 0(1500) (Crystal Barrel, WA 102) JPC = 0++ 　<< ordinary JPC mixing with ordinary mesons! [Y. Chen et al. , Phys. Rev. D 73, 014516 (2006)] Takahiro Iwata COMPASS New Frontiers in QCD, February 5, 2010

HYBRIDS Light meson sector hybrid candidate with exotics JPC=1 -+: • p 1(1400) (VES, E 852, Crystal Barrel) • p 1(1600) (E 852, VES) 35 waves 20 waves Events / 0. 04 Ge. V/c 2 still controversial. . . [A. R. Dzierba et al. , PRD 73, 072001 (2006)] M(3 ) (Ge. V/c 2) [S. U. Chung et al. , PRD 65, 072001 (2002)] Takahiro Iwata COMPASS New Frontiers in QCD, February 5, 2010

PRODUCTION MECHANISMS Central production • Rapidity gap between pslow, hfast, X • Beam particle looses ~10% of its energy • Particles at large angles from X decays • Possible source of glueballs Takahiro Iwata Diffractive dissociation • in forward direction • separate particles at very small angles • Production of Isovectors • study hybrid states New Frontiers in QCD, February 5, 2010

Diffractive Dissociation to - + p p p final State Takahiro Iwata New Frontiers in QCD, February 5, 2010

p -p -p + IN 2004 • • • Pilot run in 2004 ( 3 days ) 190 Ge. V - beam 3 mm thick Pb target Diffractive dissociation from Pomeron exchange - - +　final state (4 M events) Takahiro Iwata New Frontiers in QCD, February 5, 2010

INVARIANT MASS OF 3 system 2004 COMPASS BNL E 852 Pp=18 Ge. V/c 250 k events 0. 08<t’<1. 0 Ge. V 2/c 2 450 k events 0. 1<t’<1. 0 Ge. V 2/c 2 BNL E 852 COMPASS Acceptance COMPASS acceptance is flat 50 -60%, independent from the mass Takahiro Iwata New Frontiers in QCD, February 5, 2010

PARTIAL WAVE ANALYSIS Illinois/Protovino/Munich Program & BNL/Munich Program (independent cross-check) based on Isobar model Step 1. Mass-Independent PWA • 40 Me. V/c 2 mass bin • Gottfried-Jackson frame ( z//beam ) • 42 partial waves: JPCMe Y L Y : isobars (pp)S, f 0(980), r(770), f 2(1270), r 3(1690) • Background wave • fit in extended maximum likelihood Step 2. Mass-Dependent c 2 fit M: absolute value of the spin projection to the z axis Takahiro Iwata • fit the results of step 1 • Parameterized by Breit-Wigner • 6 waves + coherent background New Frontiers in QCD, February 5, 2010

MAJOR 　WAVES Takahiro Iwata New Frontiers in QCD, February 5, 2010

JPC=1 - + EXOTIC WAVE 1(1600): 1 -+ phase to 1++ 1(1600): 1 -+ a 1(1260): 1++ n em io ot as ph 1 -+ phase to 2 -+ 2(1670): 2 -+ 1(1600): 1 n -+ em No Non-resonant B. G. due to Deck-effect Phys. Rev. Lett. 13, 169 (1964). Submitted to Phys. Rev. Lett. Takahiro Iwata as ph io ot

p -p - p + IN 2008 190 Ge. V/c negative hadron beam; P-id by beam line Cherenkov Counter 96% -, 3. 5% K-, 0. 5% p-bar 40 cm liquid hydrogen target Spectrometer upgrade before 2008 run RPD, Silicon, Pixel GEM X 10 BNL E 852 statistics for full 2008 data Exclusive measurements Exclusivity cut [180 -190 Ge. V] After all cuts Takahiro Iwata New Frontiers in QCD, February 5, 2010

PWA FOR 2008 p -p -p + PWA has been started Illinois/Protovino/Munich Program. Same wave set (42 waves). No acceptance correction applied yet. 2++ total(e=+) Dominant waves 2 -+ total(e=+) 1++ total(e=+) Takahiro Iwata New Frontiers in QCD, February 5, 2010

Diffractive Dissociation to 0 0 p p p final State Takahiro Iwata New Frontiers in QCD, February 5, 2010

p -p 0 IN 2008 Isospin partner to p-p-p+ Consistency check Different isobars in decay chain Takahiro Iwata New Frontiers in QCD, February 5, 2010

1 ST ATTEMPT OF PWA FOR p - p 0 PWA : Illinois/Protovino/Munich Program Isobars: p 0 2++ r a 2(1280) No acceptance correction applied yet. Intensities Relative intensities of charged and neutral modes　are consistent with the isobar decays to a 2 Takahiro Iwata 1++ r 2 -+ f 2 a 1(1260) 2(1670) normalized New Frontiers in QCD, February 5, 2010

Central Production of 4 -charged-pions – – + - + (p p p fast p p p) Takahiro Iwata New Frontiers in QCD, February 5, 2010

p+ - + p p p IN CP p – p p –fast (p + p - p + p – ) pslow Study glueballs ( f 0 and f 2 families) p. X p p-fast p- + p+ pp pslow Central Production( CP) Takahiro Iwata New Frontiers in QCD, February 5, 2010

ENHANCEMENT OF CP Enhancing CP with Feynman X: COMPASS 0++ rr ? WA 102 f 1(1285) f 0(1450) f 2(1900) f 1 p+p-h p+p- (p 0) h’ p+p-h p+p- (p 0) PWA is prepared in COMPASS WA 102 (Phys. Lett. B 413: 217 -224, 1997) Takahiro Iwata New Frontiers in QCD, February 5, 2010

p p p h p, – – p p p hh p – Takahiro Iwata – New Frontiers in QCD, February 5, 2010

p -h CHANNEL p – p p – h p ( 2 g) h event selection Constraint 1 h with confidence level > 10% • exotic Jpc=1 -+ , p 1(1400) ph　? p -h 1(1400) ? • Amplitude analysis with 150 k events in progress • Better statistics expected with calorimeter calibration(2008 data) and LASER and LED monitor (2009 data) Takahiro Iwata New Frontiers in QCD, February 5, 2010

p - hh CHANNEL p – p p – h h p ( 4 g) 0 background rejected hh event selection Fit on two h mass constraint: confidence level > 10% ( for each combination) Hybrid ? 3 combinations / event Projection Takahiro Iwata p-hh New Frontiers in QCD, February 5, 2010

p - h and hh IN p - hh CHANNEL - p h 1(1400); exotic Jpc state • exotic Jpc=1 -+ , p 1(1400) ph • glueball candidate f 0(1500) hh • Structure at 1. 5 Ge. V in hh : glueball ? • Amplitude analysis with 5 k events for ph and hh in progress • Better statistics expected with calorimeter calibration(2008 data) and LASER and LED monitor (2009 data) Takahiro Iwata hh hh New Frontiers in QCD, February 5, 2010

Kaonic Final States: + – – – p p K K p p, 0 0 – – p p Ks Ks p p, …. Takahiro Iwata New Frontiers in QCD, February 5, 2010

KAONIC FINAL STATES Glueball candidates decaying into KK f 0(1380), f 0(1500): qq mixing with gg ? • Hybrid candidates decaying into KKp p(1800): usual 31 S 0 or Hybrid? Accessible channels: + – – – p p K K p p, This talk p – p Ks 0 p – p, This talk – – – + K p p p, p – p Ks 0 KL 0 p – p, …. same with positive charged beam Takahiro Iwata New Frontiers in QCD, February 5, 2010

KK SUBSYSTEM Allowed Jpc for different combinations of KK + - K K identified by RICH: 10 Ge. V/c < PK < 30 Ge. V/c Cut in acceptance RICH Neutral channels pick out the subsets Event selection Ks 0 K +K – range for kaon-id. Two displaced vertexes for Ks • 3 charged (+--) tracks • One negative track identified as K- by RICH Takahiro Iwata New Frontiers in QCD, February 5, 2010

Kp INVARIANT MASS • Expected structures for K*(892): 13 S 1 K*(1410): 23 S 1, K 0*(1430): 13 P 0 , K 2*(1430): 11 D 2 K +p - • Acceptance in the low mass region is affected by RICH threshold. • p contamination in P-id Ks 0 p Takahiro Iwata - • Almost background free • the structures are also visible. New Frontiers in QCD, February 5, 2010

KK INVARIANT MASS K+K- • Known resonances visible in both mass spectra: f 0(1500): glueball candidate f 2‘(1520): 13 P 2 Ks 0 Takahiro Iwata New Frontiers in QCD, February 5, 2010

KKp INVARIANT MASS K + K -p - • Structures around 1. 8 Ge. V and 2. 2 Ge. V Ks 0 p - Takahiro Iwata New Frontiers in QCD, February 5, 2010

Kp v. s. KKp in K+K-p - X(2. 2 Ge. V) K *(890)+ K - / Kp(1400 -1500) + K X(1. 8 Ge. V) K *(890)+ K - Takahiro Iwata New Frontiers in QCD, February 5, 2010

Kp v. s. KKp in Ks Ks p - X(2. 2 Ge. V) K *(890)+ Ks / Kp(1400 -1500) + Ks X(1. 7 Ge. V) K *(890)+ Ks Takahiro Iwata New Frontiers in QCD, February 5, 2010

KK v. s. KKp in + KK p- X(2. 2 Ge. V) (f /a 0/f 0) + p – KK(1600 ) + p X(1. 8 Ge. V) KK(1500 )+ p - Takahiro Iwata New Frontiers in QCD, February 5, 2010

KK v. s. KKp in Ks Ks p a 0(980)/f 0(980) m(Ks 0 -) /Ge. V Quite different form K+K-p- due to allowed JPC=0++, 2++, 4++ for Ks. Ks f 0(1500) f 0(1380) Takahiro Iwata m(Ks 0)/Ge. V New Frontiers in QCD, February 5, 2010

NEXT STEPS IN KKp CHANNELS • Mass-independent PWA to be performed • Enhancing central production for KK system FASTEST-p Selection Ks 0 Takahiro Iwata Ks 0 New Frontiers in QCD, February 5, 2010

CONCLUSION • COMPASS is a multi-purpose spectrometer • Muon program for nucleon spin structure • Hadron program mainly for hadron spectroscopy • COMPASS has started studies on spectroscopy • VERY high statistics ( partly > 200 times previous work) • More refined PWA is underway Status: • Exotic 1 -+ p 1(1600) has been observed in p-p-p+ channel • • • The 3 p neutral mode shows consistent signals centrally produced charged 4 p analysis is ongoing p-h, p-hh analysis is ongoing Analysis with kaonic channels is ongoing Interesting structures observed in KKp channels Takahiro Iwata New Frontiers in QCD, February 5, 2010

Backup Slides Takahiro Iwata New Frontiers in QCD, February 5, 2010

WAVE SETS IN PWA OF 2004 DATA Takahiro Iwata New Frontiers in QCD, February 5, 2010

0 -+ : (1800) IN 2004 PWA • Constant width BW for p(1800) • With low mass background Takahiro Iwata New Frontiers in QCD, February 5, 2010

- multi-g CHANNELS Selection of - n-g (n=2, n=4) events 1 outgoing negative track with Etrack < 180 Ge. V n=2 and n=4 good clusters in ECAL 1 and ECAL 2 Energy balance: 180 < E ng <200 Ge. V assuming the track to be a pion Co-planarity : -0. 3 < fpng – fp < 0. 3 rad. Takahiro Iwata New Frontiers in QCD, February 5, 2010

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 Takahiro Iwata Installed in 2005, Used in data taking from 2006 New Frontiers in QCD, February 5, 2010