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ECT* Trento, July 3-7, 2006

Study of Hadron in-Medium Properties in Antiproton-Nucleus Collisions. A. Gillitzer Institut für Kernphysik Forschungszentrum Jülich. ECT* Trento, July 3-7, 2006. Interaction of charmed hadrons with matter J/ y and y ‘ absorption In-medium mass of D mesons

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ECT* Trento, July 3-7, 2006

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  1. Study of Hadron in-Medium Properties in Antiproton-Nucleus Collisions A. Gillitzer Institut für Kernphysik Forschungszentrum Jülich ECT* Trento, July 3-7, 2006

  2. Interaction of charmed hadrons with matter • J/y and y‘ absorption • In-medium mass of D mesons • In-medium mass of charmonium states • pd collisions: DN / DN interaction • Hadrons with light anti-quarks in matter • Antikaons ( K-, K0 ) • Antibaryons ( p, L ) • Summary _ _ _ _ _ _ Outline

  3. / A + A‘  J/y(y‘) + X 400 GeV/c p + A  J/y(y‘) + X sabs = 4.2  0.5 mb J/y sabs = 9.6  1.6 mb y‘ Final NA50 result:G. Borges, JPG 30 (2004) S1351; hep-ex/0505065 B. Allessandro et al., EPJC 33 (2004) 31; EPJC 35 (2005) 335 J/y nucleon interaction J/y as indicator for QGP formation in relativistic nucleus-nucleus collisions

  4. (2) (3) (1) J/y nucleon interaction What is known about J/y absorption in nuclei? A. Sibirtsev, K. Tsushima, and A.W. Thomas, Phys. Rev. C 63 (2001) 044906 Data: (1) ~20 GeV g + Be, Ta (SLAC) R.L. Andersen et al., Phys. Rev. Lett. 38 (1977) 263 (2) 200, 450, 800 GeV p+A NA38, NA51, E772 analysis: D. Kharzeev et al., Z. Phys. C 74 (1997) 307 (3) NA50 p + A recent

  5. _ p + A  J/y + X  m+m- + X  measure cross section as function of A and pp  deduce J/yN dissociation cross section at lower, well- defned J/y momentum _ K. Seth, Proc. Hirschegg 2001, p.183 J/y nucleon interaction Measurement at PANDA : _ p + A  J/y + X  e+e- + X note: peak position sensitive to J/y mass shift in medium

  6. _ • Simulation: p + Cu  m+m- + X • background scaled up • J/y signature: • high pm, coplanarity • J/y reconstructed with sM ~ 20 MeV • rate estimate for pp on resonance: • at L = 1031 cm-2s-1 • RJ/ymm (produced)  220 /d • scan of pp & variation of Atarget •  time consuming _ _ J/y J/y nucleon interaction: feasibility

  7. J/yy‘ bpp (2.12  0.10)  10-3 (2.07  0.31)  10-4 bmm(5.88  0.10)  10-2 (7.3  0.8)  10-3 Gtot(91.0  3.2) keV (281  17) keV pp 4.07 GeV/c 6.23 GeV/c y‘ nucleon interaction  branching rates reduced by factor ~80 as compared to J/y ; enhanced by factor ~3 by larger width  yield reduced by factor ~27, i.e. Ry‘mm (produced)  8 /d  difficult

  8. vacuum nuclear medium Pb p- 25 MeV p p+ K+ K 100 MeV K- D D- 50 MeV D+ Hayashigaki, PLB 487 (2000) 96 Morath, Lee, Weise, priv. Comm. Pseudoscalar mesons in nuclear matter • p : deeply bound pionic states • K+ : momentum shift in p+A • K- : controversely discussed • D : unknown A. Sibirtsev et al., Eur. Phys. J. A 6 (1999) 351

  9. D meson spectral distribution M.F.M. Lutz, C.L. Korpa, PLB 633 (2006) 43 • prediction: • two-mode structure of D+ • UD+ +32 MeV for main branch • resonance-hole state at M ~ 1.6 GeV • repulsive D- potential: UD-  +18 MeV

  10. self-consistent D + „dressed“ p and N self-consistent D D+ meson spectral distribution L. Tolos, J. Schaffner-Bielich, A. Mishra, PRC 70 (2004) 025203 • prediction: • relatively small D • in-medium changes • broad double-hump • structure of D meson • spectral distribution

  11. _ D/D-meson mass shift: observables _ • Subthreshold DD production • enhancement of cross section • due to attractive mass shift • ( analogy to K production ) • A. Sibirtsev, K. Tshusima, A.W. Thomas, • Eur. Phys. J. A 6 (1999) 351 • quantitative result under discussion • D+ yield reduced by absorption • no information on D mass splitting • final states: D- D+ X or D- Lc X • rates at Tp = 4.5 GeV: • s ~1…10 nb, L = 1031 cm-2s-1 •  R ~ feff x (860…8600) /d _ caveat: high D momentum + _

  12. _ D/D-meson mass shift • Width of charmonium states • close to DD threshold • assumes zero mass shift of • charmonium states • collisional width may dominate • measure cc  m+m- / e+e- _ GeV/c2 Mass y(33S1) 4 y(13D1) 3.8 _ 3,74 y(23S1) vacuum 3,64 3.6 1r0 cc2(13P2) 3,54 2r0 cc1(13P1) 3.4 cc1(13P0) y(3770) 3.2 y(13S1) hc(11S0) 3 Ye.S. Golubeva et al., EPJ A 17 (2003) 275

  13. _ D/D-meson mass shifts _ • D/D transverse momentum distribution • (  J. Pochodzalla, March ’05 ) • mean transverse momentum shifted by • attractive / repulsive potential • (see determination of K+ potential at ANKE) UK+ = +20  3 MeV • size of effect: • for  p (D)  ~ 3 GeV/c,  p(D)  ~ 0.3 GeV/c, U = 100 MeV [10 MeV] •  4% [0.4%] momentum shift   p(D) shift ~12 [1.2] MeV/c; • some 10 MeV potential should be visible

  14. How to get slow D mesons ? threshold D+D- production: pp = 6.44 GeV/c  pD  3.2 GeV/c high energy D+D- production: pp = 15 GeV/c  pD  1.67 GeV/c nucleon internal momentum: for p = 3pF , pp = 6.5 GeV/c  pD  0.52 GeV/c cooperative pNN process: e.g. pd  D-Lc+ , pp = 6.5 GeV/c  pD  0.38 GeV/c 2-step process: e.g. D+d head-on collision: MD  Md  pD  0 slow D  large suppression factors conclusion: study of D mesons at rest in nuclei extremely difficult _ _ _ _ _

  15. Charmonium mass shift [1] Peskin, NPB 156 (1979) 365, Luke et al., PLB 288 (1992) 355 [2] S.H. Lee, nucl-th/0310080, Hadron 2003 proceedings [3] Brodsky et al., PRL 64 (1990) 1011 [4] Klingel, Kim, Lee, Morath, Weise, PRL 82 (1999) 3396 [5] Lee, Ko, PRC 67 (2003) 038202

  16. t ~ 10…20 fm/c final state = e+e- / m+m- / gg / J/yg  _  p  t 10 fm/c (collisional broadening) ~ 1 fm Charmonium mass shift: observables S.H. Lee (Proc. Hadron 03) predicts few 10…100 events/day at L= 21032 cm-2s-1  ~ feff (1…10) events/day at L = 1031 cm-2s-1

  17. _ • Study of pd collisions • quasi-free D+D- (D0D0,DsDs) • production • D/D, Ds/Ds „beam“ hitting the • spectator nucleon _ _ _ _ 0 • reactions e.g.: • D+ n  D0 p charge exchange • D+ n  p0 Lc charm exchange • D+ n  Ds L strangeness creation • D+ n  K0,+ Xc charm exchange & strangeness creaction • Ds n  D-L strangeness exchange • … etc., + inelastic channels •  D meson & charmed hyperon resonance spectroscopy (high s!) • needs theoretical investigation ( see A. Sibirtsev, NPA 680 (2001) 274c ) + + +,0 - Study of D+N reactions

  18. _ D.B. Kaplan, A.E. Nelson, PLB 175 (1986) 57, PLB 192 (1987) 193 • K/K mass splitting at r0 predicted • repulsive for K, (more strongly) attractive for K • free KN I = 0 interaction repulsive (  L(1405) ) • semi-empirical fit of kaonic atoms: C.J. Batty et al., Phys. Rep. 287 (97) 385 • UK = - 50 … -200 MeV • L(1405)  KNI=0 potential model: • UK = -200 MeV, small width • Y. Akaishi, T. Yamazaki, PRC 65 (2002) 044005 • UK = - 600 MeV with nuclear shrinkage • Y. Akaishi et al., PLB 613 (2005) 140 • chiral unitarity models • UK = -50 … -70 MeV, large width • M. Lutz, PLB 426 (1998) 12 • A.Ramos, E.Oset, NPA 671 (2000) 481 • L. Tolos, A. Ramos, E. Oset, nucl-th/0603033 _ _ Antikaons in nuclear matter

  19. Observation of bound K-3N & K-2N systems ? KEK: 4He(K-stpd,p/n) T. Suzuki et al., PLB 597 (2004) 263 NPA (2005) 375c BppK-115MeV FINUDA at DAFNE K-stpd on light nuclei M. Agnello et al., PRL 94 (2005) 212303 BK190MeV More hints: T. Kishimoto et al., NPA 754 (2005) 383c N. Herrmann, Proc. EXA 05, Vienna Interpretation of both KEK and FINUDA data as deeply bound kaonic states critically discussed: E. Oset and H. Toki, nucl-th/0509048 V.K. Magas, E. Oset, A. Ramos, H. Toki, nucl-th/0601013  2-nucleon absorption K-NN  SN, LN BK170MeV

  20. _ • reaction: pp ff ~ recoilless sppff 4 mb at p = 1.4 GeV/c _ JETSET: PLB 345 (1995) 325 • kinematics: pp ~ 2 GeV/c : • high momentum K+K- : • PANDA-FS: qmax 5…10o • low momentum K- • captured in bound state • low momentum K+ • reconstruct K- potential • from fK+ missing mass _ Antikaons in nuclei at PANDA + gate on L in final state after nuclear K- absortption

  21. _ pp  ff: K+, K- ptrans vs. plong distributions p = 4 GeV/c p = 4 GeV/c p = 2 GeV/c p = 2 GeV/c

  22. Antikaons in nuclei at PANDA • Feasibility: • rate: R = feff Atarget fsurv  0.7103 /h at L = 1031 cm-2s-1 • missing mass resolution: dM ~ 18 MeV for dp/p = 1% • most demanding: detection of low momentum K+ • K+ from f decay at rest (p=127MeV/c): range = 0.5 g/cm2 (C) • requires: • good dp/p resolution forward spectrometer • K identification in forward spectrometer • K+ identification in MVD by dE/dx • detection of K-N  pL/pS •  detailed simulation necessary • (K identification, nuclear background) (f) (part)

  23. p = 400 MeV/c p K p K+ identification in MVD dE/dx of p,K,p at p = 0.4 GeV/c separation power vs. momentum dE/dx simulation: T. Stockmanns

  24. _ Antibaryons in nuclei : p _ _ • Study of pA scattering, p-atoms (LEAR): •  only imaginary potential visible; real part unknown ( 0 … - 300 MeV ) • NN  NN (G-parity) : large attraction • recent theoretical study of nuclear p potential: • I.N. Mishustin et al. (Frankfurt group), Phys. Rev. C 71 (2005) 035201 • predict deep potential & surprisingly small width • PANDA: p + A  pforward + (A-1)p • measure ReU also for large ImU • determine (A-1) spectral function with p + A  p + p + (A-1)* _ _ _ _ * _ _ M(A-1)p from MMp M(A-1) from MMpp _ _

  25. _ Antibaryons in nuclei : p • Feasibility: • ds/dW(180o) = 0.26 mb/sr at pp = 0.7 GeV/c • R. Bertini et al., Phys. Lett. B 228 (1989) 531 • qcm = 20o qlab = 8o  s = 100 mb (use 50 mb for pp ~ 2 GeV/c) • rate: R = feff Atarget fp  500 /s at L = 1031 cm-2s-1 • missing mass resolution: dM ~ 18 MeV for dp/p = 1% •  momentum resolution of forward spectrometer _ (p) (p) _ (part) _

  26. _ Antibaryons in nuclei : L _ • Nuclear L potential • Indication for reduced L absorption as compared to p absorption • from L/p ratio, L A-dependence in relativistic HI collisions • PANDA : • ~2 GeV/c p + A  Lforward + (A-1)*L • detect L pp- in forward detector: • ppp- = 101 MeV/c  q < 3o • ds/dWppLL(180o) = 2 mb/sr at • p = 1.77 GeV/c  s ~ 1mb • P.D. Barnes et al. (LEAR-PS185), • Phys. Rev. C 54 (1996) 2831 • rate: • R = feff Atarget  fL  10 /s _ _ _ _ _ _ _ _ _ (part)

  27. Charm in nuclear matter • - J/y absorption: first experiments in pA  charm + X • - D/D production: inclusive D, D, and Lc detection with nuclear • targets  sensitivity to D/D potential? • - DMD/D from cc width: difficult conceptually and experimentally • - cc mass shift: cc decay inside nucleus  size of cross section ? • - pd  charm + X: access to DN / DN interaction, Lc*, Sc*, Xc* • looks feasible but needs theoretical investigation • Antikaons and Antibaryons: K, p, L in nuclear matter • - implant hadrons inside nuclei at rest • - much larger cross sections • - requires good dp/p resolution of forward spectrometer (K: slow K+ PID) • - promising approach to determine K, p, L potential _ _ _ + _ _ _ _ _ _ _ _ _ _ _ _ Summary _ _

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