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. – 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) 2012/2/102Future prospect of Hadron physics

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 Belle 2012/2/103Future prospect of Hadron physics

Beyond the quark model 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. Roper Exotics Width v.s. Mass [MeV] of Excited Nucleon Belle, PRL 99(2007), Y LEPS, PRC 79, Θ+Θ+ Need further study. 2012/2/104Future prospect of Hadron physics

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. Heavy Quark spectroscopy is key! – Many of above complex effects are suppressed. – Spin dependent interaction, Three body effects, Chiral effects Ｃ 2012/2/105Future prospect of Hadron physics

Charmed Baryons  ccc : Triple charmed baryon – It only have color interactions. – Experimentally, it’s not observed yet.  cc : 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.  + c,  c : Charmed baryons – Spin dependent interaction is suppressed – Interactions can be simplified. – Let’s start here! 2012/2/10Future prospect of Hadron physics6 Ｃ Ｃ Ｃ Ｃ Ｃ Ｃ

Single charmed Baryons 2012/2/10Future prospect of Hadron physics7 Predicted states using a quark model (L.A. Copley et. al, Phys. Rev. D 20 (1979) 768) Observed charmed baryons c c  c c  DN Threshold Several states are missing

Di-quark correlation? 2012/2/10Future prospect of Hadron physics8 Charmed baryon system can be understood as Heavy Quark – di-quark system ? “Roper”

In addition, exotics in charm sector 2012/2/10Future prospect of Hadron physics9 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

Charm Baryon J-PARC 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 2012/2/1010Future prospect of Hadron physics Several missing states and exotic candidates Observe all excited states of single charmed baryon below 3 GeV. Purpose

New J-PARC 2012/2/10Future prospect of Hadron physics11  - p ->   c + D 0  + n(d) ->   c + D 0 D 0 ->  + K - Detect , K and reconstruct D meson. Then, missing mass is calculated. Dispersive Focal Point  p/p~0.1% Construct new high resolution, high momentum beam line Beam

Experimental Setup Magnetic field: 1 [T] 50% of D meson can be detected Poor mom. res. at very forward Candidate 1: Solenoid type Candidate 2: Dipole type  2m 2m  - p ->   c + D 0  + n(d) ->   c + D 0 D 0 ->  + K - Detect , K and reconstruct D meson. Then, missing mass is calculated. Size of Gap 2m Magnetic field: 1 [T] 50% of D meson can be detected 1m1m 1m1m Size of inside coil 2012/2/1012Future prospect of Hadron physics Particle identification and trigger scheme are issues for both cases.  p/p ~ 1% is required

Kinematics & Acceptance Beam Momentum: 15GeV/c  c (2940 ) (Roper candidate) is assumed. 2012/2/10Future prospect of Hadron physics13  from D 0 decays K acc. is similar Both  and K are in acceptance Solenoid D-magnet PTPT PZPZ [GeV/c]

Momentum Resolution 2012/2/10Future prospect of Hadron physics14 Beam Momentum: 15GeV/c  c (2940 ) (Roper candidate) is assumed.  from D 0 decays K is similar Both  and K are in acceptance Solenoid D-magnet  p Z / p z D-magnet configuration has better momentum resolution. Further check for the calculation is needed  x = 100  m

2012/2/10Future prospect of Hadron physics15 PTPT PZPZ PTPT PZPZ  from  decaysProton from  decays PTPT PZPZ PTPT PZPZ Decay products from  c  from  c (2940) 3body decays  from  c (2286) decays Decayed products can be measured using the same configuration.

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. 2012/2/10Future prospect of Hadron physics16

Physics 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  (E16) Heavy ion physics 2012/2/10Future prospect of Hadron physics17

BACK UP 2012/2/10Future prospect of Hadron physics18

Note: Existing experimental results Currently, charmed baryons are identified using its decays in collider experiments. 2012/2/10Future prospect of Hadron physics19 BaBar,  c ->  K 0 s K + (Phys. Rev. D ) N ~ 4600 Our experiment measure productions of baryons and it gives different information. Statics will be similar Intensity of 10 7 ~ 10 8 / spill Sensitive to relatively wide width states Background will be suppressed at threshold region. Exclusive measurements can be done. Decays can also be measured.

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

Cross Section & Yield No reliable calculation in such threshold region – At least, 10 nb can be assumed. Yield – Lq H 2 1g/cm 2 – 10 7 / spill, 6 second – 1 baryons per spill D meson Branch and acceptance – 1% Integrated Yield per month – ~ 10 2 per month 2012/2/10Future prospect of Hadron physics21

Note: Doubly charmed meson Threshold of  momentum: 27.5 GeV –  + + p -> D 0 + D 0 +  cc ++ After upgrade of MR energy to 50 GeV, there is a hope. 2012/2/10Future prospect of Hadron physics22