1

Spectroscopy of Hyperon Resonances and Related Program at J-PARC

Hiroyuki NoumiRCNP, Osaka Univ./IPNS, KEK

YSTAR2016@JLab, Nov. 16-17, 2016

Contents

• Hyperon resonances below KbarN threshold

– KbarN interaction

– L(1405) : a dynamically generated meson-baryon state

– A role of low energy Kbar beams

• Experiment at the J-PARC K1.8BR BL

• Further studies on L(1405)

– Production rate and Form factor

– L(1405) production in Hard process: quark counting

2

L(1116), 1/2+

L(1405), 1/2-

L(1520), 3/2-

S*(1385), 3/2+

S(1192), 1/2+

KN(1432)

-27 MeV

Λ(1405) : 1405.1+1.3-0.9 MeV (PDG)

JP = ½-, I = 0, ML(1405)< MKbarN , lightest in neg. parity baryons

J. Esmaili et al: pS IM Spec. of Stopped K- on 4He

R.H. Dalitz et al: pS IM Spec. in K-p→ππΣ w/ M-matrix

M. Hassanvand et al: pS IM Spec. of pp→K+pS

L(1116), 1/2+

L(1405), 1/2-

L(1520), 3/2-

S*(1385), 3/2+

S(1192), 1/2+

KN(1432)

-27 MeV

Λ(1405) : Double pole?JP = ½-, I = 0, ML(1405)< MKbarN , lightest in neg. parity baryons

ＫＮpS

Chiral Unitary Model: D. Jido et al., NPA725(03)181

L(1116), 1/2+

L(1405), 1/2-

L(1520), 3/2-

S*(1385), 3/2+

S(1192), 1/2+

KN(1432)

-27 MeV

Λ(1405) : Need more data?JP = ½-, I = 0, ML(1405)< MKbarN , lightest in neg. parity baryons

CLAS collaboration: PRC87, 035206 HADES collaboration: PRC87, 025201

𝛾𝑝 → 𝐾+𝜋−Σ+, 𝐾+𝜋0Σ0, 𝐾+ 𝜋+Σ−

𝑝𝑝 → 𝐾+𝑝𝜋−Σ+, 𝐾+ 𝑝𝜋+Σ−

𝜋−Σ+

𝜋+Σ−

Still L(1405)?

• KbarN int. and its pole position are still unclear.

– Basic information on Kaonic Nuclei (→ H. Ohnishi)

• Not yet demonstrated if it is a molecular state.

– To establish it as an exotic state

• Hadron Picture in excited states

• New question related to classification in CQM

– Formation probability in hadronization

• ExHIC (Phys.Rev. C84 (2011) 064910)

6

Important role of Low Energy Kbar Beams

0

100

200

300

400

500

600

700

800

0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5

Y* -

YG.S

.[M

eV]

MQ [GeV/c2]

Lambda Baryons (P-wave)

7

s c

non-rel. QM:H=H0 +Vconf +VSS+VLS+VT

r-l mixing (cal. By T. Yoshida)

Sc(1/2+)

Sc*(3/2+)

Lc(2595, 1/2-)Lc(2625, 3/2-)

Lc oｒ Sc (2765, ??)

Lc(2880, 5/2+)

Lc(2940, ??)

Lc(GS)

L(1520, 3/2-)

S(1/2+)

L(1/2+)

S*(3/2+) L(1405, 1/2-)

L(1830, 5/2-)

L(1690, ??)L(1670, 1/2-)

L(GS)

l

r

b

r

Sb(1/2+) Sb

*(3/2+)

Lb(5920, 3/2-)Lb(5912, 1/2-)

Lb(GS)

Q

qq

l

r

?

T. Yoshida et al.,Phys. Rev. D92, 114029(2015)

Still L(1405)?

• KbarN int. and its pole position are still unclear.

– Basic information on Kaonic Nuclei (→ H. Ohnishi)

• Not yet demonstrated if it is a molecular state.

– To establish it as an exotic state

• Hadron Picture in excited states

• New question related to classification in CQM

– Formation probability in hadronization

• ExHIC (Phys.Rev. C84 (2011) 064910)

8

Important role of Low Energy Kbar Beams

9

Spectroscopic Study of Hyperon Resonancesbelow KbarN Threshold via the (K-,n) Reaction on Deuteron

the E31 collaboration

S. Ajimura1, H. Asano1, G. Beer2, C. Berucci4, M. Bragadireanu12, P. Buehler4, L. Busso5, M. Cargnelli4, S. Choi3,

C. Curceanu8, S. Enomoto14, D. Faso5, H. Fujioka13, Y. Fujiwara12, T. Fukuda11, C. Guaraldo8, T. Hashimoto9,

R. S. Hayano13, T. Hiraiwa1, M. Iio15, M. Iliescu8, K. Inoue1, N. Ishibashi7, Y. Ishiguro14, T. Ishikawa13, S. Ishimoto15,

T. Ishiwatari4, K. Itahashi9, M. Iwai15, M. Iwasaki9,10, S. Kawasaki1, P. Kienle16, T. Kim10, H. Kou10, Y. Ma9, J. Marton4,

Y. Matsuda13, Y. Mizoi11, O. Morra5, T. Nagae14, H. Noumi1,15, H. Ohnishi9, S. Okada9, H. Outa9, K. Piscicchia8,

M. Poli Lener8, A. Romero Vidal8, Y. Sada1, A. Sakaguchi7, F. Sakuma9, M. Sato9, M. Sekimoto14, H. Shi8, K. Shirotori1,

D. Sirghi8,12, F. Sirghi8,12, S. Suzuki15, T. Suzuki13, H. Tatsuno8, M. Tokuda10, D. Tomono1, A. Toyoda15, K. Tsukada17,

O. Vazquez Doce8,18, E. Widmann4, K. Wuenschek4, T. Yamaga1, T. Yamazaki9,13, K. Yoshida7, H. Yim19, J. Zmeskal4 .

1. Research Center for Nuclear Physics, Osaka University, Japan

2. University of Victoria, Canada, 3. Seoul National University, South Korea

4. Stefan Meyer Institut fur subatomare Physik, Austria, 5. INFN Sezione di Torino, Italy , 6.Universita’ di Torino, Italy

7. Osaka University, Japan, 8. Laboratori Nazionali di Frascati dell’INFN, Italy, 9. RIKEN, Japan

10. Tokyo Institute of Technology, Japan, 11. Osaka Electro-Communication University, Japan

11. National Institute of Physics and uclear Engineering, IFIN HH, Romania

13. University of Tokyo, Japan, 14. Kyoto University, Japan

15. High Energy Accelerator Research Organization (KEK), Japan, 16. Technische Universitat Munchen, Germany

17. Tohoku University, Japan, 18. Excellence Cluster Universe, Technische Universitat Munchen, Germany

19. Korea Institute of Radiological and Medical Sciences (KIRAMS), South Korea

measuring an S-wave ഥ𝐾𝑁 → πΣ scattering below the ഥ𝐾𝑁threshold in the d(K-,n)pS reactions at a forward angle of n.

E31 aims at:

ID’s all the final states to decompose the I=0 and 1 ampl’s.

K-

d

n

ഥ𝑲 𝝅∓,𝟎

𝜮±,𝟎𝑵

𝑵

𝝅±𝚺∓ I=0, 1 L(1405) (I=0, S wave), non-resonant[I=0/1](S(1385) (I=1, P wave) to be suppressed)

𝝅−𝚺𝟎

[𝝅−𝚲]I=1 non-resonant (S(1385) to be suppressed)

d(K-,p)p-S0 [p-L]

𝝅𝟎𝚺𝟎 I=0 L(1405) (I=0, S wave), non-resonant

Ushiwaka

CDS

D5

NCPC

K-n

d L(1405)

n

1 GeV/c ~1.25 GeV/c

~0.25 GeV/c

Cylindrical Detector System(Solenoid Field 0.7T)

K- Beam Spectrometer(K1.8BR-D5)

Beam Sweeper(Ushiwaka)

Neutron

Counter (NC)

TOF~15m

ProtonCounter (PC)

11

Experimental Setup for E31

Sp

p

CDCT0

BHDBLC2

BLC1

BPDBPC

CDH

Schematic Drawings of Detectors

• Event topology of 𝑑 𝐾−, 𝑛 𝑋𝜋±Σ∓

12

𝚺−(𝚺+)

NC

CDS𝝅−(𝝅+)

𝐧𝐊−

~15 m

CDC

CDC

n

BPD

T0

Solenoid mag.

𝝅+(𝝅−)

13

Particle ID (CDS)

𝝅+

𝝅−

𝒑

𝑲−

E31 Run Summary

14

E31 run

Beam Power

Beam Time

Executed/Proposed

pre May 2015

27 kW 2.2d ~5%

1st May-June 2016

43 kW ~7d ~30%

2nd Spring? 2017

45 kW(Expected)

~18(+2)d(request)

100%

𝑑 𝐾−, 𝑛𝜋+𝜋− 𝑛𝑚𝑖𝑠𝑠𝑖𝑛𝑔

15

Gated“𝑛” 𝑛𝜋0

Missing Mass of 𝒅 𝑲−, 𝒏𝝅+𝝅− [𝐆𝐞𝐕/𝒄𝟐]

p +

nS +

K -

p -

“n”NC

CDS

p -

nS -

K -

p +

“n”NC

CDS

16

𝑑 𝐾−, 𝑛𝜋+𝜋− "𝑛“ samples contain…

S +S -

K 0p +

n

S +K -

p -

p -

n

S -K -

p +

p +

nK 0K -

p -

S - S +K 0

p +

nS +

K -

p -

“n”

Background Events

Signal Events

𝑑 𝐾−, 𝑛 𝑋𝜋±Σ∓

p -

nS -

K -

p +

“n”

𝑑 𝐾−, 𝑛 𝑋𝜋±Σ∓ Spectrum

17

Missing mass spectrum of the 𝑑 𝐾−, 𝑛 𝑋𝜋±Σ∓ reaction

K0 and Sdecay events have been excluded.

𝐾−𝑝

𝜋+Σ−/𝜋−Σ+ Mode separation(template fitting)

18

S +

S -

pS missing mass [GeV/c2]

Co

un

ts/5

MeV

𝜋+Σ−/𝜋−Σ+ Mode (𝐼 = 0, 1)

19

𝜋−Σ+

𝜋+Σ−++

𝑑𝜎

𝑑Ω𝜋±Σ∓ =

1

3𝑓𝐼=0

2 +1

2𝑓𝐼=1

2 ±6

3𝑅𝑒(𝑓𝐼=0𝑓𝐼=1

∗ )𝑑2𝜎

𝑑Ω𝑑𝑀𝜋Σ

(Arb

itra

ry U

nit

)

𝜋+Σ−/𝜋−Σ+ Mode Average

20

𝑑𝜎

𝑑Ω𝑎𝑣 =

1

3𝑓𝐼=0

2 +1

2𝑓𝐼=1

2𝑑2𝜎

𝑑Ω𝑑𝑀𝜋Σ

(Arb

itra

ry U

nit

)

𝑑 𝐾−, 𝑝 𝑋𝜋−Σ0 Mode (𝐼 = 1)

21

Σ0

Σ0

Λ

Λ

p -

pS 0K -

p -

From 𝑑 𝐾−, 𝑝𝜋−𝜋− "𝑝𝛾" sample

𝑑 𝐾−, 𝑝 𝑋𝜋−𝜦

𝑑 𝐾−, 𝑝𝜋−𝜋− "𝒑"

22

𝜋+Σ−/𝜋−Σ+ Average (𝐼 = 0, 1)V.S. 𝜋−Σ0 Mode (𝐼 = 1)

1

2× 𝜋−Σ0 ~

1

2𝑓𝐼=1

2𝑑𝜎

𝑑Ω𝑑𝑀𝜋Σ

(Arb

itra

ry U

nit

)

1

2× 𝜋+Σ− + 𝜋−Σ+

~1

3𝑓𝐼=0

2 +1

2𝑓𝐼=1

2

• The I=0 amplitude seems dominant.

Remarks of E31 1st Run

• Structures below and above the ഥ𝐾𝑁 threshold are observed in 𝑑 𝐾−, 𝑛 𝑋𝜋±Σ∓

– Interference btw I=0 and 1.

• Pure I=1 channel, 𝑑 𝐾−, 𝑝 𝑋𝜋−Σ0, is observed.

– I=0 amp. seems dominant in 𝜋±Σ∓ modes, assuming similarity of the reaction mechanism among 𝑑 𝐾−, 𝑛 𝑋𝜋±Σ∓ and 𝑑 𝐾−, 𝑝 𝑋𝜋−Σ0.

24

In E31 2nd Run

• To measure a Pure I=0 channel, 𝑑 𝐾−, 𝑛 𝑋𝜋0Σ0

25

𝚺𝟎

NC

CDS𝝅−

𝐧𝐊−

~15 m

CDC

CDC𝜋0

γ

p

BPD

T0

Solenoid mag.

𝑑 𝐾−, 𝑛 𝑋𝜋0Σ0 mode (I=0)

26

s~3.7 MeV/c2

Λ

↳ 𝛾Λ↳ 𝑝𝜋−

Invariant Mass of 𝒑𝝅− [𝐆𝐞𝐕/𝒄𝟐]

C𝐨𝐮𝐧𝐭𝐬

p -

nS 0

K -

g

p

p0BPD

T0

π0

π0γ

(2π)0

MM of 𝐝 𝐊−, 𝒏𝒑𝝅− 𝑿 [𝐆𝐞𝐕/𝒄𝟐]C𝐨𝐮𝐧𝐭𝐬

Promising to measure with higher statistics in the 2nd Run

Further studies on L(1405)• Angular dependence of 𝑑 𝐾−, 𝑛 𝑋(𝜋Σ)0

– “Sticking probability” of ഥ𝐾 to a residual 𝑁

27

𝐼(𝑞; 𝑏0) = | 𝑓(𝑏0) 𝑗0(𝑞𝑟/ℏ) 𝑖 |2

𝑓 𝑏0 ~𝑁exp(−𝑟2/𝑏02): S wave final state

𝑞: mom. transfer (angular dependent)

The larger 𝑏0, the steeper angular dependence.

-0.4-0.200.20.40.60.811.2

-0.4-0.2

00.20.40.60.8

11.2

0 1 2 3 4 5

exp

(-r2

/b0

2)

j 0(q

r)

r [fm]

q=0.25 GeV/c

q=0.4 GeV/c

b0=2 fm

b0=1fm

b0 1fm 2fm

I (q=0.25 GeV/c) 0.69 0.3

I (q=0.4 GeV/c) 0.42 0.12

ratio 0.6 0.4

Further studies on L(1405)

• L(1405) production in Hard process (at large s, t) :

– quark counting rule: 𝑑𝜎/𝑑Ω|𝜃=90𝑜~ 1/𝑠𝑛−2

28

H. Kawamura, et al.PRD 88, 034010 (2013)

𝜋− + 𝑝 → 𝐾− + Λ(1405)

29

High-res., High-momentum Beam Line

30 GeV

proton beam

Production

Target

Pion BeamUp to 20 GeV/c

Spectrometer

T1

• High-intensity secondary Pion beam (unseparated)– 1.0 x 107 pions/sec @ 20GeV/c

• High-resolution beam: Dp/p~0.1%

K+

p-

ps-

decayp(p+)

RICH

ITOF

FiberTracker

DCDC

DCTOF

H2 TGT

In Summary

• Low energy Kbar beams are useful to study hyperon resonances.

– In particular, they play important roles on further studies of L(1405) and the KbarN.

• It is complimentary to other beams, such as high-momentum hadron beams at J-PARC.

30