1 Hadron Physics at J-PARC Shin’ya Sawada 澤田真也 KEK (High Energy Accelerator Research Organization, Japan) AFTER@LHC, ECT*, Feb. 5. 2013

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Hadron Physics at J-PARC

Shin’ya Sawada

澤田　真也KEK

(High Energy Accelerator Research Organization, Japan)

AFTER@LHC, ECT*, Feb. 5. 2013

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Contents

Overview of J-PARC and Hadron Experimental Facility (Hadron Hall)

Physics with Low Momentum Secondary Beams Physics with High-Momentum Beams Extension Summary

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Goals at J-PARC

Need to have high-powerproton beams

MW-class proton accelerator (current frontier is about 0.1 MW)

R&D toward Transmutation at 0.6 GeVNuclear & Particle Physics at 50 GeVMaterials & Life Sciences at 3 GeV

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Location of J-PARC at Tokai

TOKYO

KEK

JAERI

NARITA

KAMIOKA

Tsukuba

Tokai1 hour

295 km JAEA

J-PARC

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J-PARC Facility(KEK/JAEA ）

Bird’s eye photo in January of 2008

South to North

ExperimentalAreasNeutrino

Beams (to Kamioka)

JFY2009 Beams

50 GeV Synchrotron

Hadron Exp.

Facility

Materials and Life

Experimental Facility

JFY2008 Beams

3 GeV Synchrotron

JFY2007 Beams

Linac

Hadron Experimental Facility (Current Layout)

Hadron Hall

50GeV Synchrotron

Beam Dump

50GeV Tunnel

Ｔ１ Target(30/50% Loss)

Test BL

Hi-P BL

ExtensionSM1

(2% Loss)T0

0.1% Loss)

Switchyard

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experiments in Hadron Hall

Beam Dump

K1.8

K1.8BR

30~50 GeV primary beam

Productiontarget (T1)

Approved (stage-2) / (stage-1) / proposed,LOI

High momentum line

KL

K1.1

Hadron mass in nucleiNucleon quark structure

K1.1BRNot constructed yet

K-pp bound statesK- atomic X rays mesonic nuclei

T violation in K+ decayUniversality in K+ decay+ study by K+n scattering

-e conversion search

Hyp. weak decay( =4)AHyp. weak decay( =12)A Double charge exch. mesonic nucleip scattering

hypernuclei hypernuclei-atomic X-rays hypernuclear raysNeutron-rich hypern.Pentaquark + searchK-pp bound state

mesonic nuclei hypernuclear rays-nuclear systemsYN scatering+ hypernuclei

K0L rare decays

K-

pp

p

nSlide By H.Tamura

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Season of Fruits at Hadron Hall Comes!

Beam Intensity is being upgraded.

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Contents



Physics with Low Momentum Secondary Beams

So far there are only low-momentum beam lines. Strangeness nuclear physics

– With (pi, K), (K, pi), and (K-, K+) reactions Other hadron physics

– Many strangeness related, but a few non-strange. Low Momentum Secondary Beams

– Pions and Kaons <2 GeV/c at K1.8 beam line• Momentum was selected so that the production cross section of the Xsi

baryon is at the maximum.• Major goal is S=-2 hypernuclei (Xsi nuclei and double-Lambda nuclei).• Used also for (pi, K) reaction for single hypernuclei.

– Pions and Kaons <1.1GeV/c at K1.8BR and K1.1 beam line• Single Lambda hypernuclei

• Gamma ray spectroscopy• Search for K-pp bound states

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N

Z

Nu ~ Nd ~ Ns

Higherdensity

Strangeness in neutron stars ( > 3 - 4 0 )

Strange hadronic matter (A → ∞)

, Hypernuclei

, Hypernuclei

Str

ang

enes

s

0

-1

-2

“Stable”

Three Dimensional Nuclear Chart

Single strangeness experiments

E19 (published): Pentaquark search E10 (took data): Neutron-rich hypernuclei with

double-charge exchange E13 (coming soon): Gamma ray spectroscopy of

hypernuclei E15 (took some data): Search for K-+p+p bound state … (many waiting)

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E19: Pentaquark Search

search for Θ+ in p(π– , K–) target : liquid H2, 0.86g/cm2 at K1.8 beamline + SKS beam momentum :

– pπ=(1.87,1.92,2.00GeV/c)

4.8 x 1011 on target for each pπ

beam intensity : 107/spill(2sec.) beam time : 160 hours

Yield : 10Yield : 1044 events for each momentum events for each momentum

Sensitivity : 75nb/srSensitivity : 75nb/sr

confirm the existence of confirm the existence of ΘΘ++

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SKS: ideal for Θ+ detectionlarge acceptance : 0.1srΔM = 2.5MeV FWHM

E19 took the first physics data with p=1.92 GeV/c in Oct/Nov, 2010, and p=2.0 GeV/c in Feb, 2012.

E19: Pentaquark Search

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Study on 6ΛH hypernucleus by

the (π-,K+) reaction at J-PARC

Hitoshi SugimuraKyoto University/JAEA

For J-PARC E10 Collaboration

6/6/2013 15International Nuclear Physics Conference 2013

J-PARC E10 experiment

6/6/2013International Nuclear Physics Conference

201316

),(),( KK Double Charge-Exchange (DCX)Double Charge-Exchange (DCX)

N~Z (I=0 or 1/2)N~Z (I=0 or 1/2)

N>>Z N>>Z (I=3/2 or 2)(I=3/2 or 2)

ordinary nucleiordinary nuclei

J-PARC E10J-PARC E10

Non Charge-Exchange (NCX)Non Charge-Exchange (NCX)

hyperfragmentsby emulsions exp.

-hypernuclei-hypernuclei

),(),( KK

π-+p+p->K++n+Λ

6ΛH production by FINUDA


201317

• 66Li(stopped KLi(stopped K--,π,π++) reaction) reaction• Measured formation and weak Measured formation and weak

decay in coincidencedecay in coincidence

• cut on T(πcut on T(π++)+T(π)+T(π--))

• 3 events of candidates3 events of candidates

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HeH

HLiK66

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M. Agnello et al., FINUDA Collaboration, PRL 108 (2012) 042501M. Agnello et al., FINUDA Collaboration, PRL 108 (2012) 042501

Experimental Setup

SDC3SDC4

SFT

AC

LC

TOF

BFT

BH2 SSDBC3BC4

SDC2

BH1

GC π-

K+

J-PARC K1.8 Beam Line


•K1.8 BeamlineK1.8 Beamline-1.2GeV/c π-1.2GeV/c π-- Beam BeamΔp/p ~3.3x10Δp/p ~3.3x10-4-4

Momentum is measured by the Momentum is measured by the Transfer Matrix Transfer Matrix BFT(x)-BC3,4(x,y,x’,y’)BFT(x)-BC3,4(x,y,x’,y’)

•SKS SpectrometerSKS SpectrometerCentral Momentum 0.9GeV/cCentral Momentum 0.9GeV/cΔp/p~1.0x10Δp/p~1.0x10-3-3 Momentum is calculated or estimated Momentum is calculated or estimated Runge-Kutta methodRunge-Kutta method SFT,SDC2(x,y,x’,y’)-SDC3,4(x,y,x’,y’)SFT,SDC2(x,y,x’,y’)-SDC3,4(x,y,x’,y’)Scattered Kaon identified TOFxLCxAC in Scattered Kaon identified TOFxLCxAC in online triggeronline trigger

SKS

Calibration Runs

•Results of analysisResults of analysis +1.20GeV/c +1.20GeV/c 1212C(πC(π++,K,K++))1212

ΛΛCC - 1.37GeV/c - 1.37GeV/c p(πp(π--,K,K++)Σ)Σ--

+1.37GeV/c +1.37GeV/c p(πp(π++,K,K++)Σ)Σ++

Preliminary

Preliminary

g.s.(sΛ)

12C(π+,K+)12ΛC ΔBΛ:2.8MeV/c2

(FWHM)Ex(pΛ) p(π+,K+)Σ+ ΔM:2.6MeV/c2

(FWHM)

Preliminary

Preliminary

Measure: 1188.41MeVPDG: 1189.37MeVYield : ~2000 events

Preliminary

Preliminary

p(π-,K+)Σ- ΔM:2.5MeV/c2

(FWHM)

Measure:1200.39MeVPDG: 1197.45MeVYield : ~6000events

Σ-QFΛ-QF


Yield (g.s): ~600events

Preliminary

Preliminary

Σ-continuum

Λ-continuum

Missing Mass


201320

Missing Mass[GeV/c2]

Coun

ts/M

eV

Missing Mass[GeV/c2]

•Could measure not only Λ-continuum region but also Σ-continuum region.Could measure not only Λ-continuum region but also Σ-continuum region.•Back ground level is enough lower than Λ-continuum.Back ground level is enough lower than Λ-continuum.•According to simple extrapolation of Λ-continuum, we observed some excess According to simple extrapolation of Λ-continuum, we observed some excess at the low mass region. But it is too early to conclude at this moment. at the low mass region. But it is too early to conclude at this moment. •Production cross section ofProduction cross section of 66

ΛΛH is smaller than we expected (10nb/sr). H is smaller than we expected (10nb/sr).

E13: Hypernuclear Spectroscopy

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High-precision (E ～ 3 keV FWHM) spectroscopy with Ge detectors

1. YN, YY interactions Unified picture of B-B interactions Understand short-range nuclear forces Understand high density nuclear matter (n-star) 　　 Level energies ->N spin-dependent forces, Charge symmetry breaking, N-N force,…

　　　　　　2. Impurity effects in nuclear structure Changes of size/shape, symmetry, cluster/shell structure,.. B(E2), E(2+) -> shrinking effect, deformation change

3. Medium effects of baryons probed by hyperons B(M1) -> in nucleus E13

E13

Double-strangeness hypernuclei soon

With the improvement of the proton beam intensity, double-strangess experiments with (K-, K+) become possible soon.

E07: Systematic Study of Double Strangeness System with an Emulsion-Counter Hybrid Method

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PS-E176in ~80 Ξstops

Double-Hypernucleuswith sequential decaysurely exists.

5

6ΛΛ

He 4 H

e t

Ξ-

p

π-

Λ

He

10μm

500

10

5

ΔB = 1.01±0.20 MeV

in ~700 Ξstops

10

5

0 5 10(m)

A

B

#1

#2#3

#2

Ξ

#1

+6 cand.NAGARA event

for 6He

PS-E373

Double-strangeness hypernuclei soon

E07: Systematic Study of Double Strangeness System with an Emulsion-Counter Hybrid Method

– Physics 1) S=-2 nuclear chart by ~102 Z via 104

--stopping events.

=> B of several nuclides will provide definitive informationon interaction and structure of S=-2 nuclei.

2) H-dibaryon state in S=-2 system ?

=> measure A-dependence of B & decay mode of Z.

3) -nucleus potential

=> detection of twin hypernuclei => First measurement of X-ray of -atom

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Contents



Physics with High-Momentum Beams

“High-momentum beam line” (+ COMET beam line) has been funded!

High-momentum primary proton beam (30GeV)– Meson mass modification inside nuclei– Dilepton measurement for nucleon and baryon structure

High-momentum meson (pion) beam (~<15 GeV/c)– Pion-induced Drell-Yan?– Baryon spectroscopy with pion beams.

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High-p and COMET

New primary Proton Beam Line= High-momentum BL + COMET BL

High-momentum Beam Line– Primary protons (~1010 – 1012pps)

• E16 (phi meson) is considered to be the first experiment.

– Unseparated secondary particles (pi, …)• High-resolution secondary beam by adding several quadrupole and

sextupole magnets.

COMET– Search for to e conversion– 8 GeV, 50 kW protons– Branch from the high-momentum BL– Annex building will be built at the south side.

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New Primary Proton Beam Line

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COMETHigh-p

Separation

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Mass modification of vector meson

Hot/Dense Matter

Tqq

,

Vector meson massat normal nuclear density

m*/m=1-k Hatsuda&Lee PRC46(92)R34) m = 130 MeV at m = 20~40 MeV at

RestorationChiral Symmetry

QCD Vaccum

Spontaneous Breaking of

Results of a previous experiment (KEK-PS E325):Invariant mass spectra of e+e-

Results of a previous experiment (KEK-PS E325):Invariant mass spectra of e+e-

<1.25 (Slow) 1.25<<1.75 1.75< (Fast)

Larg

e N

ucle

usSm

all N

ucle

us

PRL 98(2007)04250129

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J-PARC E16: Electron pair spectrometer to explore the chiral symmetry in QCD

107 interaction (10 X E325) 1010 protons/spill with 0.1% interaction length target GEM TrackereID : Gas Cherenkov　　 + Lead GlassLarge Acceptance (5 X E325)

primary proton beam at high momentum beam line　　　　　　　 + large acceptance electron spectrometer

velocity dependencenuclear number dependence (p Pb)centrality dependence　 systematic study of mass modification

Possible hadron exps at high-momentum BL

Sea quark structure through Drell-Yan measurement– Currently the E906/SeaQuest is running at Fermilab with 120-GeV protons

to see d-bar/u-bar asymmetry.– Larger x possible with 50-GeV protons at J-PARC.

• J-PARC is currently operated with 30-GeV and there are no demands of 50-GeV operation from other experiments, which needs modification of a part of the accelerator components.

– There could be other possibilities of physics with dimuon measurement such as,

• J/Psi measurements to see the nucleon sea,

• dimuons from pion/kaon induced reactions to see meson-like substructure of a nucleon.

Spin related quantities– Polarized beam relatively far future.

– Polarized target would be available in the near future.

– Measurement such as Bohr-Mulders can be carried out even with unpol. Drell-Yan measurements.

J/Psi: gg or q-qbar?

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E866data : ( ) / 2 ( )p d X p p X

/ 2 [1 ( ) / ( )] / 2Drell-Yan:

/ , : / 2 [1 ( ) / ( )] / 2

pd pp

pd ppn pJ

d x u x

g x g x

Lingyan Zhu et al., PRL, 100 (2008) 062301

Gluon distributions in proton and neutron are very similar at 800 GeV. At much lower energies, J/Psi might be produced by q-qbar annihilation. Azimuthal angle dependence. If J/Psi production is q-qbar annihilation, J/Psi becomes a tool to investigate quark structure of nucleon at lower energies.

Unseparated Secondary Beam Intensity

beam loss limit @ SM1:15kW (limited by the thickness of the tunnel wall)

[GeV/c]

extraction angle ： 5° smaller angle possibility being investigated

with 15kW beam loss

Exclusive Pion-Induced Drell-Yan Process

*( )q

2small ( )t q q 2large ( )t q q

: pion distritribution amplitude (DA) TDA : -N transistion distritribution amplitude

•DA characterizes the minimal valence Fock state of hadrons.•DA of pion are also explored by pion-photon transition form factor in Belle and Barbar Exps.

•TDA characterizes the next-to-minimal valence Fock state of hadrons.•TDA of pion-nucleon is related to the pion cloud of nucleons.

Bernard Pire , IWHS2011

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Accident

Radiation accident occurred at Hadron Hall on May 23rd.– Due to a malfunction of the beam extraction system of the 50 GeV synchrotron, a

proton beam was delivered to the gold target of the Hadron facility within a very short time (30GeV, 2E13protons in ~5ms). As a result, the gold target is considered to have momentarily reached an extremely high temperature and a part of the target was damaged. Radioactive material then leaked into the hadron experimental hall and some workers were externally and/or internally exposed to radiation.

– Operation of ventilation fans of the hall resulted in leak of radioactive material out of the radiation controlled area of the Hadron Experimental Facility. The data logs of radiation dose rates at monitoring posts at the border of the J-PARC site showed no signatures. However, at three monitoring posts and stations of a neighboring JAEA facility, momentary increases of the radiation dose rate were observed. It is assessed that the released radioactive material was diluted and attenuated as it dispersed in a narrow strip towards the west. The maximum integrated radiation dose has been estimated even at the site boundary closest to the Hadron Experimental Facility was 0.29 µSv (preliminary).

– All the J-PARC facilities have been shutdown since the accident. A full investigation of the cause of the accident is now underway along with the complete review of safety practices and emergency procedures at all J-PARC facilities. Our first priority is to restore public trust in the facility by developing and implementing measures to prevent the reoccurrence of an accident and to provide a safe experimental environment for users and workers.

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Summary

Physics experiments have started at the Hadron Hall of J-PARC, and the first physics paper is being published from the E19 experiment. So far experiments with lower momentum pions/kaons are being carried out.

The funding for the high-momentum beam line with COMET has been approved by the government. The construction is expected to start soon. Mass shift of phi meson would be the first experiment, and other experiments are being discussed.

J-PARC is now very busy to respond to the accident. We don’t have any forecast on the schedule, but we make our best.

Documents

1 Hadron Physics at J-PARC Shin’ya Sawada 澤田 真也 KEK (High Energy Accelerator Research Organization, Japan) AFTER@LHC, ECT*, Feb. 5. 2013

1 Hadron Physics at J-PARC Shin’ya Sawada 澤田真也 KEK (High Energy Accelerator Research Organization, Japan) AFTER@LHC, ECT*, Feb. 5. 2013