Hadron spectroscopy in photo- and hadroproduction at COMPASS p. 1/13

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1 Hadron spectroscopy in photo- and hadroproduction at p. 1/13 Hadron spectroscopy in photo- and hadroproduction at Jan Friedrich Physik Department, TU München on behalf of the collaboration

2 Outline The Experiment Φ(186) search with muon beam structure and spectroscopy with hadron beam pilot run 24 pion polarisability measurement diffractive processes Jan Friedrich, TU München 24. October 25 Hadron spectroscopy in photo- and hadroproduction at p. 2/13

3 - Spectrometer COmmon Muon and Proton Apparatus for Structure and Spectroscopy fixed target experiments at SPS/CERN hadron beam: /spill, 1-25 GeV muon beam: /spill, 16 GeV polarised 6 LiD target trigger covers also small Q 2 data taking since events, L 2/fb Jan Friedrich, TU München 24. October 25 Hadron spectroscopy in photo- and hadroproduction at p. 3/13

4 Hadron spectroscopy in photo- and hadroproduction at p. 4/13 Physics muon beam gluon polarisation G/G longitudinal/transverse spin distributions Λ polarisation muoproduction of hadrons dominated by quasi-real photoproduction hadron beam hadron structure via Primakoff effect charmed baryons gluonic systems exotic hadrons diffractive reactions Jan Friedrich, TU München 24. October 25

5 The pentaquark anti-decuplet Φ Ξ π or Σ K ddssū nk + or pk uudd s Z + (153) N(171) Ξ π + Σ(189) or Σ + K uuss d D. Diakonov, V. Petrov, M. Polyakov, Z. Phys. A359 (1997) [hep-ph/973373] Ξ 3/2 (27) Baryon resonances J = 1 2 with Γ 2-2 MeV Citation: S. Eidelman et al. (Particle Data Group), Phys. Lett. B 592, 1 (24) and 25 partial update for edition 26 (URL: Θ(154) + I (J P ) = (?? ) Status: A REVIEW GOES HERE Check our WWW List of Reviews Θ(154) + MASS Citation: S. Eidelman et al. (Particle Data Group), Phys. Lett. B 592, 1 (24) and 25 partial update for edition 26 (URL: Φ(186) I (J P ) = 3 2 (?? ) Status: OMITTED FROM SUMMARY TABLE Jan Friedrich, TU München 24. October 25 Hadron spectroscopy in photo- and hadroproduction at p. 5/13

6 NA49 C. Alt et al, Phys. Rev. Lett (24) Entries / 7.5 MeV/c a) b) M(Ξπ) [GeV/c 2 ] search for decay chain Φ(186) Ξ π Λ π π p π π π peak at 1862 MeV FWHM 17 MeV after kinematical cuts S = 67.5, σ= 5.6 p-p collisions Jan Friedrich, TU München 24. October 25 Hadron spectroscopy in photo- and hadroproduction at p. 6/13

7 Φ(186) Search X Ξ π ± Λ π π ± p π π π ± Entries / 1 MeV Ageev et al, EPJ C41 (25) 469, M(pπ - ) - M(Λ) [MeV] M(pπ + ) - M(Λ) [MeV] 1 7 Ξ(153) 92 Ξ(153) 18 Ξ 1 6 Ξ Λ 64 Λ Λ X Ξ + π ± Λ π + π ± p π + π + π ± Jan Friedrich, TU München 24. October 25 Hadron spectroscopy in photo- and hadroproduction at p. 7/13

8 Φ(186) Search X Ξ π ± Λ π π ± p π π π ± Entries / 1 MeV Ageev et al, EPJ C41 (25) 469, M(Λπ - ) - M(Ξ - )[MeV] M(Λπ + ) - M(Ξ )[MeV] 1 7 Ξ(153) 92 Ξ(153) 18 Ξ 1 6 Ξ Λ 64 Λ X Ξ + π ± Λ π + π + π ± p π + π + π ± Jan Friedrich, TU München 24. October 25 Hadron spectroscopy in photo- and hadroproduction at p. 7/13

9 Φ(186) Search X Ξ π ± Λ π π ± p π π π ± Ageev et al, EPJ C41 (25) 469, 22-3 Entries / 7 MeV Ξ - π + mass [MeV] Ξ + π - mass [MeV] 1 7 Ξ(153) 92 Ξ(153) 18 Ξ 1 6 Ξ Λ 64 Λ X X Ξ + π ± π ± Λ Λ π + π ± p π + π + π ± Jan Friedrich, TU München 24. October 25 Hadron spectroscopy in photo- and hadroproduction at p. 7/13

10 Result Ageev et al, EPJ C41 (25) 469 Entries/ 7 MeV Position of the NA49 signal Entries/ 7 MeV Position of the NA49 signal M(Ξ π - )(GeV) M(Ξ π + )(GeV) Entries/ 7 MeV Position of the NA49 signal Entries/ 7 MeV Position of the NA49 signal M(Ξ π - )(GeV) π + )(GeV) Jan Friedrich, TU München 24. October 25 - M(Ξ S < 7 at 99% CL (scaled NA49 would be S 4) Hadron spectroscopy in photo- and hadroproduction at p. 8/13

11 Other Φ(186) searches Jan Friedrich, TU München 24. October 25 Hadron spectroscopy in photo- and hadroproduction at p. 9/13

12 Soft hadronic reactions at Pilot hadron run (3 weeks in Oct/Nov 24) 19 GeV/c π beam (1 6 /s) on Pb, Cu, C targets muon runs (to check with pointlike projectile) trigger on events with small-angle scattered pion Hadron Setup 24 top view Veto Trigger Silicons Straws SM1 Hadron Calorimeter1 SM2 Hadron Muon Calorimeter2Filter2 EM Calorimeter2 Primakoff trigger Beam Killers Straws π Beam x Target VetoBox SciFi System MicroMeGas SciFi SDC Gem Scifi SDC RICH MWPC GEM SciFi Iarocci Tubes SciFi GEM MWPC DC SciFi GEM MWPC MWPC Drift Tubes z Muon Filter m Jan Friedrich, TU München 24. October 25 Hadron spectroscopy in photo- and hadroproduction at p. 1/13

13 Primakoff reactions 4 35 π + Pb π + Pb + γ pole at Q 2 selects electromagnetic πγ ( ) π γ (Compton scattering in inverse kinematics) > 1 11 pion beam flux 4 Primakoff events expected at least 4 more statistics than previous Serphukov measurement method to extract pion polarisabilities complementary to Mainz γp nπ + γ measurement t [GeV/c] M(πγ) Jan Friedrich, TU München 24. October 25 Hadron spectroscopy in photo- and hadroproduction at p. 11/13

14 Diffractive reactions Example: π + Pb Pb + π π π + (exclusive) at low t Total energy of the 3 outgoing particles 25 Momentum transfer (exclusive events) Energy [GeV] t [GeV /c ] study of angular distributions (PWA) in preparation potential to reveal exotic objects (as 1 + π 1 resonances) Jan Friedrich, TU München 24. October 25 Hadron spectroscopy in photo- and hadroproduction at p. 12/13

15 Summary finds no evidence for the Φ(186) pentaquark in muoproduction The signature of Primakoff reactions is seen with pion beam. Potential to measure Kaon polarisability! The hadron program has a large potential for contributing to the spectroscopy sector s. also S. Platchkov: nucleon spin and structure J. Nassalski: gluon polarisation A. Sandacz: diffractive ρ production R. Joosten: transversity A. Bressan: Collins and Sivers asymmetries Jan Friedrich, TU München 24. October 25 Hadron spectroscopy in photo- and hadroproduction at p. 13/13