j-parc japan proton accelerator research complexsakemi/future/slide/sawada.pdfsecondary beams:...

July 26, 2003 核物理の将来検討会 1

J-PARCでのハドロン物理

Shin’ya Sawada (KEK)Naohito Saito (Kyoto)

Yasuhiro Sakemi (RCNP)


Contents

Overview of J-PARCNuclear and particle physics experimental Hall for extraction Hadron physics at J-PARCDimuon measurement– Physics goals– Experimental apparatus and simulation– Future


Accelerator Configuration

Cascaded Accelerator Complex:

400MeV Linac

3GeV Rapid Cycling (25Hz) Synchrotron

50GeVSynchrotron

Materials and Life Science Facility

Nuclear and Particle Physics Facility


Phase 1 & 2

The budget for about 2/3 of the entire project has been approvedgovernment from JFY2001 as Phase 1.Phase 1 (~135 billion Yen) consists of major accelerator and a part of experimental facilities.

50-GeV PS will provide 30-protons (slow) at Phase 1.


Construction Schedule & Commissioning

Item

Linac Bldg

Linac Accel

3GeV Bldg

3GeV Accel

3GeV Exp Bldg

3GeV Exp Fac

50GeV Bldg

50GeV Accel

50GeV Exp Bldg

50GeV Exp Fac

Power 0.1% 1% 10％～ 100％

Beam Test

3GeV BT

Installation

10％～ 100％

Beam Test

Construction

Installation

Beam TestInstallationConstruction

Beam TestConstruction Installation

Power 0.1% 1% 10％～ 100％

Installation

Beam Test

Beam Test

Construction Installation

Start Usage

Test Period▲

Open to Users

Year2001 2002 2003 2004 2005 2006 2007 2008 2009

Construction

Power 0.1% 1%

Two Big Phase 2 ProjectsNeutrino (Budget request sent to MEXT)Transmutation

No


Nuclear Physics Programs

Slow beams– Hypernuclear/strangeness physics– Hadron physics

• Protons and mesons from Phase 1• Heavy ions and polarized protons in the future

Fast beams– Antiproton physics– Neutrino-nucleus scattering

RCNPなどの外部機関がまとまった形でプログラムを展開するた

の条件

– 「旗」がたてられること

– 適正な人的、金的規模、ある程度年次計画が見えること

遅い取り出しビームを用いたハドロン物理を提案。


NP Hall

Slow extracted beam~200m switching yard + Phase 1– One target station, one (or

secondary line.– 30GeV operation.– No research/preparation

building.– Easy extension to the beam

direction.


Hadron Physics at J-PARC

Several Letters of Intent– Measurement of the spin rotation parameters A and R in the

region of pi-N elastic scattering– Analyzing power An in 50 GeV very-high-PT2 proton-proton elastic

scattering– Electron pair spectrometer at the JHF 50-GeV PS to explore the

symmetry in QCD– Hadron spectroscopy at J-PARC– Construction of a high momentum beam line at the 50-GeV Proton

Synchrotron– Physics of high-mass dimuon production at the 50-GeV Proton

Synchrotron– Energy dependence of intermediate-mass fragment angular – Lifetime measurement of pi+pi- and pi+-K-+ atoms to testlow energy – A hadron spectroscopy experiment with RF-separated high energy

beam at JHF


Outline of Proposed Dimuon Measurement

Collaboration named on the LoI– Abilene Christian, ANL, Duke, KEK, Illinois, Kyoto, LANL, MIT, TIT– Contact persons: J.C. Peng and S. Sawada

Physics Goals– dbar/ubar at large x– Antiquark distribution in nuclei– Quark energy loss in nuclei– u-quark at large x– Drell-Yan angular distributions– Drell-Yan with transversely polarized target– dbar/ubar via J/Psi production– J/Psi nuclear dependence– J/Psi with transversely polarized target


Deep Inelastic Scattering and Drell-Yan

10-10

10-8

10-6

10-4

10-2

1

10 2

10 4

10 6

10 8

10 10

10 12

0.08 0.09 0.1 0.2 0.3 0.4 0.5 0.6

l l

l

l

Drell-Yan

DIS


Dimuon Experiments at FNAL

FNAL E605/772/789/866 with 800 GeV protons

1

10

10 2

10 3

10 4

10 5

2 4 6 8 10 12 14 16

J/ψ

ψ′

ϒ

ϒ′ ϒ″

Mass (GeV/c2)

Cou

nts/

0.1

GeV

/c2

• Closed geometry

•Vertical bending

Two compnents: Drell-Yan (continuum) vector mesons


dbar/ubar Flavor Asymmetry

0.6

0.7

0.8

0.9

1

1.1

1.2

1.3

0 0.05 0.1 0.15 0.2 0.25 0.3 0.35

CTEQ4M

CTEQ5M

GRV98MRST

“CTEQ4M (d_ - u

_ = 0)”

Drell-YanJ/ψϒ(1S)ϒ(2S)

x2

σpd/2

σpp

FNAL E866/NuSea Drell-Yan

1% Systematic error not shown

Drell-Yan:

J/Psi, Upsilon (800 GeV):

σ pd

2σ ppx1 >> x2

≈12

1+d (x)u (x)

+≈

>>)()(1

21

221

xgxg

p

n

xxpp

pd

σσ


dbar/ubar at Large x using 50 GeV Protons

DY cross section is ~16 times larger at 50 GeVthan at 800 GeV.

2121

, fixedat 1 xxsdxdx

d DY ≈σ


Quark Bremsstrahlung in Nuclear Medium

Landau-Pomeranchuk-Migdal (LPM) effect of medium modification for brems has been observed at SLACLPM effect in QCD remains to be identified.

– DIS: dE/dx ~ 0.5 GeV/fm (PRL 89 162301)

– DY: dE/dx ~ 2.5 +- 0.6 GeV/fm (PRL (2001) 4483)

Quark energy loss dE/dx is predicted be proportional to L2.Enhanced quark energy loss in quark-gluon plasma.Quark energy loss in cold nuclei be better measured!

(GeV/c)Tp0 1 2 3 4 5 6 7 8 9 10

R

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

2=200 GeVNNs

neutral pions

- dAu min. bias (PbGl)dAR

- dAu min. bias (PbSc)dAR

- AuAu 0-10% centralAAR


Quark Energy Loss with DY at 50 GeV

Fractional energy loss is larger at 50 GeV. Effect is amplified.Possible to test the L dependence of the LPM effect the A dependence.


J/Psi Production at 50 GeV

At 800 GeV, J/Psi production dominated by gluon-gluon fusion process.

At 50 GeV, J/Psi production dominated by quark-annihilation process.J/Psi production at 50 (and GeV is sensitive to quark antiquark distributions.


dbar/ubar asymmetry via J/Psi at 50 GeV

Ratio of p+d J/Psi over p+p J/Psi is sensitive to dbar/ubar.At 30 GeV, J/Psi production could also be well


Dimuon with polarized beam/target

If polarized protons can be accelerated –– Helicity distribution of sea quarks

• meson-cloud model: negligible sea-quark polarizationchiral-quark soliton model: large polarization

• Measure double-helicityALL

DY.

Even if only the target can be polarized –– Transverse single spin asymmetry transversity– “Sivers effect” due to initial state gluon exchange ”Collins effect”

final state fragmentation– Only Sivers effect can contribute to DY asymmetry.

• Semi-inclusive DIS, such as HERMES, contains Collins effect also.

Lines correspond to different parmetrizations (i.e. different models).


Spectrometer

Two vertically bending with pT kick of 2.47 GeV/c0.5 GeV/c.“Closed geometry”– A tapered copper beam

and Cu/C absorbers placed within the first magnet.

Tracking is provided by three stations of MWPC and drift chambers.Station 4 provides muon id tracking.2x1012 50 GeV p/spill.

Dump and Absorber

Station 1 Station 2

(Station 3 and 4)


High Momentum Beam Line

Primary beams: proton (Phase 1), polarized proton heavy ions (future)Secondary beams: proton, pion, kaon, anti-proton,

The radiation shielding of the SY tunnel designed so that 2% (15kW) loss SM1.

Exp. setup could be staged.

~120m


Proposal

Interesting and important physics issue for nuclear community.Strong support from the community is necessary for manpower and funding.Expertise of RCNP people, especially on polarized targets must fit for realization of the project.

Construction of high momentum beam line and leading role in the experiment especially for polarized construction.

j-parc japan proton accelerator research complexsakemi/future/slide/sawada.pdfsecondary beams:...

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