佐甲博之 (ASRC/J-PARC, JAEA)

ELPH研究会 C024

「ハドロン構造における多粒子相関」

1

J-PARCにおけるハドロンビームを用いたバリオン共鳴の研究 (E45 and E72)

1. J-PARC E45 (N*, D* spectroscopy)

2. J-PARC E72 (L(1670))

3. Preparation status of experiments

4. Summary

2

J-PARC E45

Studies of baryon resonances in (p,2p) reactions

Goals

• Establish N* and D* resonances up to 2 GeV/c2

• Search for new baryon states– e.g. hybrid baryons (qqqg)

• Deeper understanding of non-perturbative QCDp

N

N*

pp

N

3

J-PARC E45 Collaboration

K. H. Hicks, S. Chandavar, W. Tang, T. Chetry, N. Compton, M. Mroz (Ohio Univ)

H. Sako, K. Imai, S. Hasegawa, S. Sato, K. Tanida, J. Yoshida, Y. Ichikawa (Japan Atomic Energy Agency)

K.Y. Baek, S. H. Park (Pusan National Univ)

J.K. Ahn, J.W. Lee, S.H. Kim, W.S. Jung, M.H. Kim, J.B. Park (Korea Univ)

J.Y. Lee, T. Moon (Seoul National Univ.)

H.S. Lee (IBS)

H. Fujioka, S. Nakamura, M. Niiyama, H. Ekawa (Kyoto Univ)

K. Ozawa, H. Sugimura, H. Kamano (KEK)

K. Nakazawa, S. Kinbara (Gifu Univ)

S. H. Hwang (KRISS)

B. Bassalleck (Univ New Mexico)

K. Joo, N. Markov, N. Harrison, T. O’Connell, E. Seder, A. Kim, D. Riser, F. Cao, B. Clary, P. Hornung(Univ Connecticut)

B. Briscoe, F. Klein, I. Strakovsky, R. Workman (George Washington Univ)

R. Schumacher (Carnegie Melon Univ)

D. M. Manley (Kent State Univ)

L. Guo (Florida International Univ)

P. Cole , A. Forest, D. McNulty (Idaho State Univ)

T.S.-H. Lee (Argonne National Lab)

T. Sato, Y. Nakada (Osaka Univ)

K. Shirotori, S. Y. Ryu (RCNP, Osaka Univ)

Y. Azimov (Petersburg Nuclear Physics Institute)

V. Shklyar (Univ Giessen)

A. Svarc (Ruder Boskovic Institute)

S. Ceci (RBI-Zagreb)

M. Hadzimehmedovic, H. Osmanovic (Univ Tulza)

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Baryon spectroscopy :Physics of broad and overlapping resonances

N(1

44

0):

Ro

per

N(1

53

5)

✓ Width: a few hundred MeV.

✓ Resonances are highly

overlapped in energy

except D(1232).

→Partial Wave Analysis

to extract hidden resonances

Measure cross sections as a

function of

• Incident pion energy

• Scattering angle

In broad range (with fine bins)

to extract resonance poles

D.H.Perkins, Introduction to High Energy Physics

p+p

p-pResonances in PDG

4PDG 2017

PDG data for N* and D* resonancesMany resonances have not been established experimentally.

* ********* Established

Most of the N*s so far were

measured from

pN→ppN data necessary to resolve

remaining resonances

D(1600) 3/2+ ***Roper-like radial excitation state• Determination of mass is important to

understand Roper-like resonances• Only p+p→ ppN data of E45 can determine

its mass precisely

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World’s pN→ppN dataOnly 240K events measured in 1970’s

H. Kamano et al., PRC 79 025206 (2009).

No channel

coupling

With channel

coupling

W : ppN CM energy

Dynamical Coupled Channel model (ANL-Osaka)

Inclusion of intermediate meson-baryon

channels :

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Importance of ppN Decay

H. Kamano, et al. PRC 79 025206 (2009)

Wid

th o

f N

* re

so

na

nc

es

(M

eV

)

8

Recent Lattice QCD calculations

No

te: N

ot

rea

l m

ass!

J. Dudek et al., PRD85 (2012) 054016

Hybrid baryons

(qqqg)

N(939)

Measurement of (p,2p) in large acceptance TPC (HypTPC)

p+- beam on liquid-H2 target

p-p→p+p-n, p0p-p

p+p→p0p+p, p+p+n

2 charged particles + 1 neutral particle

→missing mass

pN→KY (2-body reaction)

p-p→K0L,

p+p→K+S+ (I=3/2, D*)

LH2 target

Hyperon Spectrometer for E45

HypTPC

Superconducting

Helmholtz magnet

Trigger with hodoscope

p beam

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Expected statistics of E45• p beam rate : 106 / spill (2s)

• Liquid H2 target : 5 cm thick

• TPC acceptance : 40%

• (p,2p) cross section : ~2 mb (p+p→p+p+n)

160 events / spill

・ pp CM energy range : 1.50 – 2.15 GeV (p= 0.73 – 2.0 GeV/c)

・No. of bins : p- beam : 24 (energy) x 20 (angle)

p+ beam : 23 (energy) x 20 (angle)

・No. of events / bin : 32 K

30M events in 15 days

Increase world’s ppN data (0.24M) by a factor of 13010

J-PARC E72

Search for a Narrow L*

Resonance using the p(K-,L)hReaction

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E72 Collaboration• Japan Atomic Energy Agency: S. Hasegawa, T. Hashimoto,

Y. Ichikawa, K. Imai, H. Sako, S. Sato, K. Tanida

• Ohio University: Taya Chetry, Gleb Fedotov, Ken Hicks, Joey Rowley, Utsav Shrestha

• RCNP, Osaka University: H. Noumi, K. Shirotori, S.B. Yang

• University of Connecticut: Kyungseon Joo, Nikolay Markov, Andrey Kim, Stefan Diehl, David Riser, Brandon Clary, Thomas O'Connell, Frank Cao, Kevin Wei

• Florida International University: L. Guo

• RIKEN: M. Iwasaki, S. Okada, F. Sakuma, H. Asano, Y. Ma

• ELPH, Tohoku University: H. Ohnishi, A. Tokiyasu

• Korea University: J.K. Ahn, S.W. Choi, W.S. Jung, B.M. Kang, S.H. Kim, K.Y. Roh, H.M. Yang

• INFN Frascati: Alberto Clozza, Catalina Curceanu, Kristian Piscicchia, Alessandro Scordo

• Kyoto University: M. Niiyama

• Korea Research Institute of Standards and Science: S.H. Hwang

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E72: Search for a new narrow L*(1670)

Hints for L*(1670) from previous experiments

D(1232)

L(1520)

K*(896)

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1D projection - 𝑀 𝑝𝐾−

𝑀 𝑝𝐾− [GeV/c2]

Cou

nts

/ 1𝑀𝑒𝑉/𝑐

2

Crystal Ball at BNL

K-p → Lh[PRC64.055205])

Belle: Λc+ → 𝑝𝐾−𝜋+[PRL117.011801]

Peak: ~1663 MeV

near Lh threshold

(1663.5 MeV)

Width: ~10 MeV

ds

/dW

(mb/s

r)

1669MeV

1679MeV

1664MeV

~hL thres

L Polarization in CB dataNo new resonance

3/2+ (P03)

1671+2-8 MeV

G=10+22-4 MeV

Kamano et al.[PRC92.025205]

1669 MeV 1683 MeV3/2- (D03)

1668.5±0.5 MeV

G=1.5±0.5 MeV

No new resonance

To distinguish between P and D waves,

100 times more statistics than CB is required 14

Liu and Xie[PRC86.055202]

E72 setup

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HypTPC

LH2

Target

Helmholtz

magnet

(B=0.6 T)

TPC

Hodoscope

K- beam

K-p → Lh

• Reconstruct L→ pp- in TPC

• Identify h w/ missing mass

• Trigger in hodoscope

• 2 charged particles

• proton with large DE

Beam momentum: 735

MeV/c (±2%) at K1.8BR

300k events in 2 weeks

(100 times of CB data)

Hyperon Spectrometer

Hyperon Spectrometer Status

-HypTPC-〇 Octagonal prism field cage〇 Inner target system → Large Acceptance〇 Triple GEM layers

(50 + 50 + 100 μm thick)〇Gating gridMaximum beam rate : 106Hz

〇~6000 readout pads~2.4×11 mm2

〇 Gas: Ar-CH4(9:1) (vdrift ~ 5.3 cm /μs)〇 Gain ~ 104

〇 Position resolution < 300 μm〇 Δp/p = 1-3% for π and p

Gating Grid

Triple GEM

Readout pads

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HypTPC test with high-rate proton beams

at HIMAC (Aug 2018)

Track reconstruction

Required performance confirmed up to 106 Hz

(position resolution, efficiency, etc.)

Beam

events

Reaction event

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Efficiency / plane Horizontal position resolution

TPC Hodoscope

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Beam

Hodoscope– Surrounding HypTPC for trigger and

PID

– 32 segments (70*800*10 mm3)

– MPPC used as a light sensor

– Timing resolution of ~110 ps

– PID: using dE/dx (TPC), TOF, and

p/q.

at σT = 150 ps

PID: dE/dx(TPC) vs p/q PID: TOF(β) vs p/q

MPPC

80

0m

m

70

mm

Light guide

Coil current

Upper coil T Lower coil T

Superconducting Helmholtz magnet

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B field up to 1.3 T

• Transverse B component in TPC

volume <1%

Excitation test at KEK in Mar. 2019

• Operation successful for 118 hours (5

days) at 1.0 T (70 A).

Field mapping done in May 2019

Coils

Cryostat

Return yoke

Field mapping

(May 2019)

Liquid H2 target• Target system

completed in 2018

• Test of lifting

system going on

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HypTPC

Target

lifting

system

LH2 target

system

Summary

E45 : Study of baryon resonances in (p,2p) reactions– Establish N* and D* resonances up to 2 GeV/c2 with

130 times more statistics than previous data– Search for hybrid baryons

E72 : Search for a new L* (1670) resonance

• Measurement of p(K-,L)h– 100 times more statistics than Crystal Ball

– Differential cross section and L polarization

→ Parity determination

Hyperon spectrometer

• Large acceptance spectrometer for E45 and E72 based on Helmholtz magnet and HypTPC

• The spectrometer will be ready by the end of JFY201921