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Hadron Spectroscopy with high momentum beam line at J-PARC

Hadron Spectroscopy with high momentum beam line at J-PARC. K. Ozawa (KEK). Contents Charmed baryon spectroscopy New experiment at J-PARC. On-going Joint Project. Joint project between J-PARC theory center, KEK, and RCNP.

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Hadron Spectroscopy with high momentum beam line at J-PARC

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  1. Hadron Spectroscopy with high momentum beam line at J-PARC K. Ozawa (KEK) • Contents • Charmed baryon spectroscopy • New experiment at J-PARC

  2. On-going Joint Project • Joint project between J-PARC theory center, KEK, and RCNP. • Proposing construction of new high-momentum high-resolution beam line • Collaboration • H. Kamano, T. Nakano, H. Noumi, A. Hosaka (RCNP), T. Sato (Osaka) • M. Oka, T. Hyodo (TIT), D. Jido(Kyoto) • K. Ozawa, S. Yasui (KEK) Future prospect of Hadron physics

  3. Hadron Physics • Origin of Hadron interaction? • Nuclear Force inside nuclei • Meson-Baryon, Baryon-Baryon interaction • Property of Nuclear (QCD) matter? • Origin of hadron mass • Neutron Star • Inside structure of Hadron? • Naïve quark model needs to be extended • Roper, Penta quark , Exotic mesons @ Belle Future prospect of Hadron physics

  4. Beyond the quark model Roper • According to the naïve quark picture, the first excited state should be negative. • However, observed state is positive. (It’s called Roper.) • Long standing problem • In addition, several exotic hadrons are observed recently. Width v.s. Mass[MeV] of Excited Nucleon Exotics Belle, PRL 99(2007), 142002 Θ+ Y LEPS, PRC 79, 025210 Need further study. Future prospect of Hadron physics

  5. Issues and Solution • Several effects are competed in light hadrons • Gluon interaction , Chiral properties, Di-quark correlation, Three body effects, Spin dependent interaction, Dynamical orbital excitation • Current experimental data includes all above effects. • Every effect should be measured separately. Ｃ • Heavy Quark spectroscopy is key! • Many of above complex effects are suppressed. • Spin dependent interaction,Three body effects,Chiral effects Future prospect of Hadron physics

  6. Charmed Baryons Ｃ Ｃ • Wccc : Triple charmed baryon • It only have color interactions. • Experimentally, it’s not observed yet. • Xcc : Doubly charmed baryons • Effects of chiral symmetry are suppressed. • Other effects can be studied easily. • One experiment (SELEX) reported. • It can be produced at J-PARC. • L+c, Sc : Charmed baryons • Spin dependent interaction is suppressed • Interactions can be simplified. • Let’s start here! Ｃ Ｃ Ｃ Ｃ Future prospect of Hadron physics

  7. Single charmed Baryons Predicted states using a quark model (L.A. Copley et. al, Phys. Rev. D 20 (1979) 768) Observed charmed baryons Threshold DN Several states are missing Scp Lcp Future prospect of Hadron physics

  8. Di-quark correlation? Charmed baryon system can be understood as Heavy Quark – di-quark system “Roper” ? Future prospect of Hadron physics

  9. In addition, exotics in charm sector • If exotic baryons exist in charm sector, it can be observed easily compared to light quarks. • Narrow width • Large mass window below DN threshold Candidate of exotics Mass window for exotics Future prospect of Hadron physics

  10. Charm Baryon spectroscopy @ J-PARC Several missing states and exotic candidates Purpose Observe all excited states of single charmed baryon below 3 GeV. • Mass Spectra of excited charmed baryon contains basic information of quark interaction • Many states are still missing • Few states are observed in invariant mass plot. • Observed states has relatively narrow width • Good for spectroscopy! Roper candidate Observed charmed baryons Future prospect of Hadron physics

  11. New Experiment @ J-PARC Beam p- p -> S0c + D0 D0 -> p+ K- p+ n(d) -> L+c + D0 Detect p, K and reconstruct D meson. Then, missing mass is calculated. Construct new high resolution, high momentum beam line Dispersive Focal Point Dp/p~0.1% Future prospect of Hadron physics

  12. Experimental Setup p- p -> S0c + D0 D0 -> p+ K- p+ n(d) -> L+c + D0 • Magnetic field: 1 [T] • 50% of D meson can be detected • Poor mom. res. at very forward Detect p, K and reconstruct D meson. Then, missing mass is calculated. dp/p ~ 1% is required Candidate 1: Solenoid type Candidate 2: Dipole type 1m Size of Gap Size of inside coil 1m f2m 2m 2m • Magnetic field: 1 [T] • 50% of D meson can be detected Future prospect of Hadron physics Particle identification and trigger scheme are issues for both cases.

  13. Kinematics & Acceptance • Beam Momentum: 15GeV/c • Lc (2940 ) (Roper candidate) is assumed. p from D0 decays K acc. is similar Both p and K are in acceptance Solenoid D-magnet PT PZ 2 0 4 8 0 1 [GeV/c] [GeV/c] Future prospect of Hadron physics

  14. Momentum Resolution • Beam Momentum: 15GeV/c • Lc (2940 ) (Roper candidate) is assumed. p from D0 decays K is similar Both p and K are in acceptance Solenoid D-magnet DpZ/ pz Dx = 100mm D-magnet configuration has better momentum resolution. Further check for the calculation is needed. -0.1 0 0.1 Future prospect of Hadron physics

  15. Decay products from Lc PT PZ PT PZ p from Lc(2940) 3body decays p from Lc(2286) decays PT PZ PT PZ p from L decays Proton from L decays Future prospect of Hadron physics Decayed products can be measured using the same configuration.

  16. Summary • To understand structure of light hadrons, charmed baryon spectroscopy is an important tool. • charmed baryon spectroscopy can give basic information about Roper state, Exotic state, and di-quark correlations. • A new beam line and new experiment is proposed to perform charmed baryon spectroscopy. Future prospect of Hadron physics

  17. Physics topics @ new beam line • Charm baryon bound state • Color transparency • Short range structure • Drell-Yan process (P04) • c-bar c contents in nuclei • Multi-fragmentation • omega bound state (E26) and eta’ • Basic cross section of pi N -> pi pi N • Exotic in light quark • Mass modification of f (E16) • Heavy ion physics Future prospect of Hadron physics

  18. Back up Future prospect of Hadron physics

  19. Note: Existing experimental results • Currently, charmed baryons are identified using its decays in collider experiments. • Our experiment measure productions of baryons and it gives different information. • Statics will be similar • Intensity of 107 ~ 108 / spill • Sensitive to relatively wide width states • Background will be suppressed at threshold region. • Exclusive measurements can be done. • Decays can also be measured. N ~ 4600 BaBar, Lc -> LK0sK+ (Phys. Rev. D72 052006) Future prospect of Hadron physics

  20. The J-PARC E16 spectrometer Magnet (used for KEK E325) X 26 Candidates of large D-magnet spectrometer

  21. Cross Section & Yield • No reliable calculation in such threshold region • At least, 10 nb can be assumed. • Yield • Lq H2 1g/cm2 • 107 / spill, 6 second • 1 baryons per spill • D meson Branch and acceptance • 1% • Integrated Yield per month • ~ 102per month Future prospect of Hadron physics

  22. Note: Doubly charmed meson • Threshold of p momentum: 27.5 GeV • p+ + p -> D0 + D0 + Xcc++ • After upgrade of MR energy to 50 GeV, there is a hope. Future prospect of Hadron physics

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