J-PARC での YN 相互作用の研究

J-PARCでの YN相互作用の研究東北大学理学研究科

三輪浩司

Contents Physics background

YN interaction Scattering experiment , spectroscopy

Past experiments of YN scattering What did we learn?. What should we improve?

Experiment at J-PARC LH2, Fast IIT, Scifi-MPPC

R&D of Scifi-MPPC Performance for MIP, proton

e+ beam test @ LNS proton beam test @ CYRIC

Outlook Trigger, Multi-channel readout

Nuclear force

regV

rmc

What is the origin?Color magnetic interaction

ij

jijiji

s ssFFmm

AHH ))((0 meson exchange picture

NN interaction

interaction Isospin 3/2Spin 1

Quark Pauli effectStrong repulsive force

More exchange mesons• K• K*,

To SU(3) flavor symmetry

Baryon-Baryon interaction

NN interaction special aspect of BB i

nteraction BB interaction

Effect of new quark Different aspect of u,

d quarks N

exchange is forbidden.

N (S,T)=(1,3/2) quark Pauli effect

S=0 NN(T=1) S=-1 N(T=3/2) N-N(T=1/2) S=-2 (T=2) N--(T=1) N--(T=0)S=-3 (T=3/2) - (T=1/2)S=-4 (T=1) S=0 NN(T=0)S=-1 N-N(T=1/2)S=-2 N-(T=1)S=-3 (T=3/2)

S=-1 N(T=3/2)S=-2 N--(T=1)S=-3 - (T=1/2)S=-4 (T=0) S=-1 N-N(T=1/2) S=-2 N-(T=1) N--(T=0)S=-3 - (T=1/2)

S=-1 N-N(T=1/2) S=-2 N-(T=1) N(T=0)S=-3 - (T=1/2)

S=-2 N--(T=0)

Experimental investigation of YN interaction

2body interaction pp, np scattering deuteron

Tensor force

Spin dependent force Structure of Nuclei

Large LS force Polarized pp, np scatter

ing

2body interaction Bubble chamber Poor data

SU(3) framework Spin dependent force

Structure of Hypernulei

1950

NN interaction

YN interaction

npnp pppp pp p0p

p+p pp p0n pn

At J-PARC!70

90×

YN scattering observables

Precise measurement Model selection

Meson exchange model Quark model

RGM-F

NSC

HC-DHC-F p scattering

N(N)=N(beam)/10000 More Hyperon beam

More fast imaging

YN scattering experiment at KEK

Important parameter Production of

1cm Scifi (CH) (from free proton) 1M/spill beam KURAMA spectrometer acceptance

(, ) 1.8mb 9 / spill (, ) 0.5mb 2 / spill

Scattering of

Mean flight legth ~ 1.3cm (p) ~ 10mb (assumption) 1600 1 p scattering

Production target 2cm CH2 + 2cm CH

Free proton 54

Quasi free 118

Important parameter2

(, )

(, )

1M/spill 10M/spill

5M/spill 50M/spill 500M/spill 5000M/spill

172/spill 1720/spill 17200/spill 172000/spill

p scat 0.1/spill 1/spill 10/spill 100/spill

We need Fast Imaging deviceWe need high quality trigger

@ 1M K

R&D works for fast imaging Ieiri

High-Speed Image Delay Tube Image duration

Electron drift

J.K. Ahn LH2 target (No Imaging)

Detect all state particle with spectrometer Miwa

Scifi-MPPC readout Fast imaging + spectrometer

Read out system of SCIFI using MPPC’s Multi-Pixel Photon Counter (MPPC)

New Si photo-diode consisted of multipixel of Avalanche Photo Diode (APD) operating in Geiger Mode

100 ～ 1600 pixels of APD in MPPC Output signal is the sum of each pixel

Characteristics Fast time response ( < 10ns)

It can operate in the high beam intensity

Large gain (105106) Possible to detect 1 photon

Operation at the magnetic field IIT can not work at the magnetic field

Can we use this detector for hyperon scattering experiment using a high intensity beam ?

1mm

1mm

At J-PARC 1st target is p scattering production via (, ) reaction　 using a 1.1GeV/c K-

beam Forward spectrometer＋ Cylindrical spectrometer

Concept of whole experimental setup

Zoom up

To be studied

MIP Light yield Enough

efficiency

Slow proton Dynamic range Range analysis Total energy

deposit

p

p

Performance check for MIP

LNS-Tohoku, test beam lineWith 450MeV Positron beam

2007/Jan20ch MPPC readout

Performance for MIP particle Prototype of Scifi-MPPC

system Readout of 20ch MPPC e+ beam

1mmx1mm Fiber 20 ch

Scinti. Fiber

MPPC

Connection between Fiber and MPPC

MPPC

Fiber

Photon number for MIP Identification of beam

Required hits of upstream and downstream fibers

Required these hits two photon

Check the photon number

Performance for proton

Tohoku Univ. CYRIC80MeV proton beam

2008/June50ch readout

Purpose of this experiment Response of Scifi-MPPC system for proton

Light yield Momentum resolution from Range Radiation hardness

Momentum range of proton in YN scattering exp.

Total 0~1.2GeV/c Stop in Scifi 0~0.4GeV/c This momentum range is accessible in CYRIC (80MeV proton)

Experimental setup Primary Proton beam

Ekin = 77.52 MeV 1~5nA

Secondary proton beam pp scattering (11~42MeV)

Primary target CH2

30, 100, 300 m Fiber bundle

5segment x 10 layer 1mmx1mm

Vacuum chamber 10-3 Pa

77.52MeV p

pp’

Trigger counter12cm from targetEntrance 3mm

Fiber 5segment x 10layer20cm from target

Data List

(deg) trigger

’(deg) fiber

Ekin(MeV)

Range (mm)

23 67 11.3 1

27 63 14.3 2

30.5 58.5 18.8 4

35.5 55 23 5

38 52 27.4 7.3

39.5 49.5 30.0 8

45 45 34.7 11

50 40 42.1 16

CH2 targetp

p

Scifi

Trigger counter

p beam 77MeV

Angle scan

pp scattering

Momentum selected proton beam to Scifi

Signal of proton Raw signal

Proton ~250mV 1p.e. ~4mV

Dynamic range (400pixel) 1p.e. (1pixel) ~ 10ch 34MeV proton ~ 120pixel Stopping proton ~ 300pixel

Trigger selection Proton OK Stopping proton OK

MIP

regi

on

Proton stop

Proton pass through

~250mV

(single photon ~ 4mV)

40ns

Stop layer and Total energy depositStop layer Total energy

Trigger possibility Identify of scattering proton

Total Energy deposit 1 scattering / 100 cut events ( >22MeV)

Number of particle + each energy deposit

p

Detect 3 particles with counter

2 particles Counter1 stopping particle Energy deposit

Multi-channel readout Total channel of MPPC

~5000 ch We have to serialize the readout (like SSD). Serializing chip Flash ADC

Requirement of serialize Fast time response

10MHz Trigger generation

Chip VA chip? (slow?) APV25 (50ns peaking time)

Summary We want to reveal new aspects of B.B. interaction

N, N, N We need high intensity beam

~10MHz, ~ 100MHz We have to develop high speed imaging device

Fast image delay tube MPPC readout

MPPC readout MIP

mean photon number ~6 photon Proton

Dynamic range is enough. Works well as range counter. Stopping proton can be triggered easily.

Further works Trigger possibility Multi-channel read out

Typical image (Ekin=30MeV)

YN scattering experiment at KEK Scintillation fiber and IIT-

CCD KEK-PS E289, E452 p, p, p elastic scattering Feasibility of SCIFI active

target

reaction Event number

E289p 31p 30p ----

E452 p 113

ProblemIIT-CCD is slowThere are overlaps of image @ beam intensity > 300kHzDetection of all particles in the final state is difficult

Experimental investigation of YN interaction Hyperon-Nucleon Scattering

Difficult due to short lifetime of hyperon Poor data compared to NN scattering

Structure of hypernuclei High resolution magnetic spectrometer Gamma-ray spectroscopy using Ge detector

Problem Derive two body force from complex many body sy

stem N interaction, N interaction ？

npnp pppp pp p0p

p+p pp p0n pn

大きさについて

Advantage of detecting all particles in the final state

Remove the quasi free scattering SCIFI consists of CH Quasi-free scattering with proton in carbon nuclei should

be separated from the scattering with free proton.

Scattered p + from

n from

p

Scat’ : Momentum　 Scat’ angle

Proton: Mom, AnglePrediction

Proton: Mom, AngleMeasurement

MeasurementConsistency checkRemove quasi free

Momentumproton(GeV/c) (degree)

Free proton

Quasi free scattering

Photon number for MIP

Mean photon number ~6 photon Efficiency ( > 2 photon) ~ 95%

Mean photon number

> 1photon> 2photon

Operation in Magnetic Field

Photon number with magnetic field Photon number Gain

e+ beam

Magnet

FiberB Field

Do NOT change due to the magnetic field

We can use this Scifi-MPPC system as an imaging detectorinside the magnetic spectrometer