HIGH STATISTICS SPSCATTERING EXPERIMENT

AT J-PARCKoji Miwa (Tohoku univ.)for the E40 collaboration

CollaboratorsTohoku Univ. : T. Aramaki, N. Chiga, N. Fujioka, M. Fujita, R. Honda, M. Ikeda, Y. Ishikawa, H. Kanauchi, S. Kajikawa,

T. Koike, K. Matsuda, Y. Matsumoto, K. Miwa, S. Ozawa, T. Rogers, T. Sakao, T. Shiozaki, H. Tamura,H. Umetsu

JAEA : S. Hasegawa, S. Hayakawa, K. Hosomi, Y. Ichikawa, K. Imai, H. Sako, S. Sato, K. Tanida , T.O. Yamamoto,

J. Yoshida

KEK : Y. Akazawa, M. Ieiri, S. Ishimoto, I. Nakamura, S. Suzuki, H. Takahashi, T. Takahashi, M. Tanaka, M. Ukai

RIKEN : H. Ekawa

Chiba Univ. : H. Kawai, M. Tabata

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Kyoto Univ. : S. Ashikaga, T. Gogami, T. Harada, M. Ichikawa,T. Nanamura, M. Naruki, K. Suzuki

Osaka Univ. : K. Kobayashi, S. Hoshino, Y. Nakada, R. Nagatomi, M. Nakagawa, A. Sakaguchi

RCNP : H. Kanda, K. Shirotori, T.N. Takahashi

Okayama Univ. : K. Yoshimura

Korea Univ. : J.K. Ahn, S.H. Kim, W.S. Jung, S.W. Choi, B.M. Kang

OMEGA Ecole Polytechnique-CNRS/IN2P3 : S. Callier, C.d.L. Taille, L. Raux

Joint Institute for Nuclear Research : P. Evtoukhovitch, Z. Tsamalaidze

Contents

YN interaction and Sp scattering

Analysis status– S-p, S-p à Ln scatterings– S+p scattering

Summary

Strategy of hypernuclear physics

Nuclear physics

Known nuclear force

Unknown nuclear structure

Hypernuclear physics

Unknown YN interaction

Expect from hypernuclear structure

Theoretical frameworkextended to SUF(3) symmetry

Lattice QCD

Hyperon proton scattering

12C(p+, K+)12LC

PRC 64 044302 (2001)

g-ray spectroscopyPRL 87 212502 (2001)X hypernuclear spectroscopy

sd-shell L hypernuclei

10 times more LL hypernuclei

Hyperon proton scattering

Current status of YN scattering experiment

NN scattering data : quite accurate

YN scattering data : very poor statistics

np®np pp®pp Lp®Lp Lp®S0p

S+p®S+p S-p®S-p S-p®S0n S-p®Ln

Y. Kondo Doctor thesis

Comparison of BeamProton beam (1012~13 particle / pulse)

flight length : ~80 m

flight length : ~1.2 cm

Secondary beam (p, K) (107 particle / pulse)

Third beam (S, L)(~100 particle / pulse)even in E40 experiment

J-PARC E40 : Measurement of ds/dW of Sp scatterings Physics motivations

– Verification of repulsive force due to quark Pauli effect in the S+p channel– Systematic study of the SN interaction by separating isospin channel

Measurement of ds/dWAim to detect 10,000 events• S+p elastic scattering• S-p elastic scattering• S-p à Ln inelastic scattering

Pauli effect in quark level

S+p potential by Lattice QCD

H. Nemura et al.Few-Body Syst (2013) 54:1223-1226

Large repulsive core is expected in Lattice QCD

Large ds/dW is predicted in S+p channel

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10 550MeV/c NSC97f550 MeV/c FSSfss2ESC08Chiral EFT 550 MeV/cE289 data (0.35<p(GeV/c)<0.75)E251 data (0.3<p(GeV/c)<0.6)

p mode0πn mode+π

Cross section in simulation

p scattering at 0.5 < p (GeV/c) < 0.6)+Σ (Ω/dσd

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n scattering (0.45 < p(GeV/c) < 0.55)L ®p -SSimulationCross section in simulation500MeV/c NSC97f500 MeV/c fss2ESC08500 MeV/c chiral EFT

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p scattering at 0.55 < p(GeV/c) < 0.65)-S (W/dsdSimulationCross section in simulation600MeV/c NSC97fESC08600 MeV/c fss2600 MeV/c chiral EFTE289 data (0.4<p(GeV/c)<0.7)

Our goal

I=3/2S+p (0.5 < p (GeV/c) < 0.6)

S-p (0.55 < p (GeV/c) < 0.65) S-p → Ln (0.55 < p (GeV/c) < 0.65)

Theories– Quark Cluster model (FSS, fss2)

Y. Fujiwara et al., Prog. in Part. and Nucl. Phys. 58 (2007) 429, and private communication

– Nijmegen model (ESC08c) T. A. Rijken, Prog. of Theor. Phys. Suppl. 185

(2010) 14, and private communication– Chiral EFT (NLO)

J. Haidenbauer et al., Nucl. Phys. A 915 (2013) 24, and private communication

I=1/2

Quark Pauli effect

Constraint for Chiral EFT

Information of LN-SN coupling

Simulation

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1k2 sin2 δ3S1 =

dσdΩ

(900 )− (higher waves)

Phase shift of quark Pauli channel

Experiments at J-PARC

Easier to check experimental feasibility

S- : Longer life timeNo decay channel to proton

S-n

p-

1st production run S-p scattering in June 2018 (~2 days)

2nd production runS-p scattering production run in 2019 Feb. – March (~20 days)

17 M S-S+p scattering production run in 2019 April (~13 days)

40 M S+

3rd production runS+p scattering production run in 2020 Feb. - March

2018

2019

2020Due to accelerator trouble, half of beam time was postponed.

BC3,4(MWDC)

BH2

BH1GC

BFT

π+

CATCH

KURAMAK+

E40 detector setup concept

S production– p±p→K+S±

1.3 GeV/c p- 1.4 GeV/c p+

S momentum range– 0.4 ~ 0.8 GeV/c

Beamline spectrometer• Momentum analysis of

p beam

KURAMA spectrometer• Identification of K+

• Momentum analysis

Momentum reconstructionof S beam

p+

Two successive two-body reactions

p+ K+

p

n (missing)

CATCH systemCylindrical Fiber Tracker

BGO calorimeter

p+

Detection of Sp scattering eventby CATCH detector

J-PARC K1.8 beamline

S Identificationp+

K+

p

Mass2 (GeV2)

BC3,4(MWDC)

BH2

BH1GC

BFT

π+

CATCH

KURAMAK+ Analysis of forward

spectrometer

Analysis of beamline spectrometer S-

Missing mass (GeV)

Missing mass (p-pàK+X)

Mass square distribution of outgoing particle

S beam momentum distribution

S- beam momentum distribution S+ beam momentum distribution

GeV/c GeV/c

S- yield : ~17 M (Our goal 18M)ct = 4.4 cm

S+ yield : ~40 M (Our goal 80M)ct = 2.4 cm

Derive differential cross section for three momentum ranges to understand beam momentum dependence

Sp scattering detector (CATCH)– Compact setup to satisfy both K+ acceptance and Sp scattering acceptance– Fast response detector to reject accidental coincidence events

p+400 mm

49 mm35 mm

100 mm

pK+

S

p

p n

pS

Ep

q

Cylindrical Fiber Tracker + BGO calorimeter configuration

CFT

BGO

BGO E (MeV)

CFTD

E (M

eV)

CATCH Particle ID w/ S- event

Proton with S- event !

S- : No major decay mode to proton

Sign for some reaction

Missing mass

Missing mass (GeV/c2)

S-

Proton event in S- production

a

Proton event in S- production

anp scattering

p-p scattering

DEnp (MeV) Dpp-p (MeV)

DE = Emeasured – Ecalculated (q)

Proton event in S- production

anp scattering

p-p scattering

DEnp (MeV) Dpp-p (MeV)

S-p scattering

~4500 event

DES-p (MeV)

preliminary

S-p à Ln

~2400 event

DpS-p->Ln (MeV)

preliminary

DE = Emeasured – Ecalculated (q)

Angular dependence

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p scattering at 0.55 < p(GeV/c) < 0.65)-Σ (Ω/dσd

600MeV/c NSC97f

ESC08

600 MeV/c fss2

600 MeV/c chiral EFT

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n scattering (0.45 < p(GeV/c) < 0.55)Λ →p -Σ

500MeV/c NSC97f

500 MeV/c fss2

ESC08

500 MeV/c chiral EFT

out o

f acc

epta

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Before acceptance and efficiency correction

DE S

-p(M

eV)

cosqCM

preliminary preliminary

Dp S

-p->L

n(M

eV)

cosqCM

Forward peak structure Rather flat structure

Angular dependence

a

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p scattering at 0.55 < p(GeV/c) < 0.65)-Σ (Ω/dσd

600MeV/c NSC97f

ESC08

600 MeV/c fss2

600 MeV/c chiral EFT

CMθcos-1 -0.8 -0.6 -0.4 -0.2 0 0.2 0.4 0.6 0.8 1

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n scattering (0.45 < p(GeV/c) < 0.55)Λ →p -Σ

500MeV/c NSC97f

500 MeV/c fss2

ESC08

500 MeV/c chiral EFT

out o

f acc

epta

nce

Before acceptance and efficiency correction

DE S

-p(M

eV)

cosqCM

preliminary preliminary

Dp S

-p->L

n(M

eV)

cosqCM

Forward peak structure Rather flat structure

We could collect enough data to study the angular dependence with good accuracy.We will also check the S- beam momentum dependence.

S+p analysis

Experimental difficulty– Many protons from S+àpp0 decay– Much shorter flight length (~ 1.2 cm )

S+ à p + p0 decay event

p0

MM2 (GeV2)Start from 2 proton final event

S+ decay make a large background in S+p scattering for S+àp+n decay mode

Two proton event in S+ productionS+p scattering pp scattering from S+ decay

pp opening angle

Dp (pp scattering)

pp scattering

q pp

(deg

)

Kinematical check of pp scattering

Dp (GeV/c)

Clear identification of pp scattering

Detectors work well

S+p scattering

~40 M S+ beam

S+p scattering event ~2500

DE (MeV)

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550 MeV/c FSS

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p scattering at 0.5 < p (GeV/c) < 0.6)+Σ (Ω/dσd

S+p scattering

Before acceptance and efficiency correction

out o

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cosqCM

DE S

+p(M

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preliminary

Summary YN interaction from Yp scattering

– We have to establish this new direction

S yield summary

– S-p : 17M (94%)

– S+p : 40M (50%)

Analysis is on going

– Every scattering reaction is confirmed well Background reactions

Sp scattering reactions

– We can provide sufficient data to discuss the angular distribution of C.S.

– We could establish the modern Yp scattering experimental technique.

Future prospects– Derivation of ds/dW– U/D asymmetry of proton from hyperon decay for spin observable measurement

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