K. Ozawa (KEK) - INDICO (Indico)...GEM Tracker Electron ID Magnet We construct new beam line and...

K. Ozawa (KEK)

K. Ozawa, ANPhA symposium, Jeju, Korea

15/June/2019 2

J-PARC (Japan Proton Accelerator Research Complex)

Tokai, Japan

MR30 GeV Synchrotron

400 MeV LinacRCS

3 GeV Synchrotron

Material and Life Science Facility

Neutrino Experimental Facility

Hadron Hall60m x 56m

Hadron Experimental Facility

15/June/2019K. Ozawa, ANPhA symposium, Jeju, Korea 3

Hadron Experimental Facility

K1.8BR

KL

K1.8

K1.1High-p

COMET

Name Species Energy IntensityK1.8 π±, K± < 2.0 GeV/c ~105 Hz for K+

K1.8BR π±, K± < 1.0 GeV/c ~ 104 Hz for K+

K1.1 π±, K± < 1.1 GeV/c ~ 104 Hz for K+

High-pproton 30GeV ~ 1010 Hz

Unseparated < 20GeV/c ~ 108 HzUnder Construction

Production Target


Nuclear properties are being intensively studied at HIAF, RAON, and RIKEN.

In addition to studies at these facilities, we can probe inside of nucleus using higher energy proton beam at J-PARC. Strange (and charm) hadrons can be generated and implanted to

nucleus Interactions between mesons and nucleons can be studied directly Nuclear matter effects on hadron properties can be measured

These studies are also important to understand properties of neutron star.

In near future, we will have heavy ion beams and explore high density quark-hadron matter. See the next talk

As a result, we can perform very comprehensive studies for nucleus, nuclear matter, and high density quark-hadron matter in Asia region!


Let’s think about baryons which contain a strange quark.

Such baryons can avoid a “Pauli-blocking” and we can put it deep inside a nucleus.

Such baryons have a similar energy state with a nucleon and we can study nucleon state levels in nucleus directly.

At KEK-PS, an experiment is performed to study baryon states in nucleus.

PRC 64 (2001) 044302

-> UΛ = - 28 MeV(c.f. UN ~ -50 MeV)

Strange baryon (Λ) states measured by Prof. Nagae

This method is a powerful tool to study hyperon interactions

4ΛH

p

n

Λ4

ΛHe

T.O. Yamamoto et al.,PRL 115 (2015) 222501

Emulsion dataM. Juric et al. NPB 52 (1973) 1

∆E(4ΛHe)-∆E(4

ΛH) = 320 keV >> B(3H)-B(3He) ~70 keV

Λ

pn

Bedjidian et al.PLB 83 (1979) 252 etc.

π−A. Esser et al.,

PRL 114 (2015) 125012.12±0.01±0.09


Energy levels of A=4 mirror hyper nuclei

Large charge asymmetry is suggested !!

Slide from Prof. H. Tamura


To study a finite density system, understanding of three-body system is important.Especially, K-NN system is interesting

Attractive K-N interaction in I=0 is suggested by properties of Λ(1405) A bound state of K-pp system is predicted by several theoretical calculations

Various predicted values of binding energy and widthExisting experimental data is not agree with theoretical predictions

J-PARC E15: Prof. Iwasaki (RIKEN)A new experiment is executed using a new technique!


E15 collab., PLB789(2019)620.

• Binding energy: ~50 MeV

• Width: ~100 MeV

Invariant mass distribution of Λp

Quasi-Free and Background contributions are evaluated using missing mass information

Ξ-N is attractive !

K. Nakazawa et al. PTEP 2015, 033D02

=

p8Li8Be

α

α

p d

e

Kiso event

Ξ- + 14N -> Ξ15C -> Λ10Be + Λ5He


∼ ∆BΛΛ= 1.87±0.37 MeV*

H. Ekawa, PTEP 2019, 021D02

p ΛMino event

Λ-Λ is weakly attractive

10µm

Ξ-

ΛΛBe

4HeH

16O + Ξ- → ΛΛBe + 4He + H

*There are other interpretations


Nucleus can be considered as a finite density nuclear matterAt the high density limit, hadrons can’t keep their forms and become quarksEven at the transition phase, hadron properties can be modified

Proton ~ 940 MeV/c2 Quark ~ a few MeV/c2

The one of the most significant difference between hadrons and quarks is its “Mass”

If we can measure this “mass” in a finite density matter, the measurements provide crucial information for the hadron-quark transition

The most suitable probe for this purpose is mass of vector mesons, sinceMvector meson ~ 2 Mquark


HADES (G. Agakishiev et al. Eur. Phys. J. A 48 64 (2012).) Enhancement in low mass region

CBELSA/TAPS (Phys.Rev. C82 (2010) 035209) Modification of ω is not observed

J-LAB CLAS G7 (PRL 99 (2007) 262302) Mass broadening of ρ due to hadronic effects Large Width of φ (Phys. Rev. Lett. 105 (2010) 112301)

LEPS (Phys. Lett. B608 (2005) 215) Large Width of φ

KEK-PS E325 (PRL 96 (2006) 092301, PRL 98(2007) 042581) Peak shift and width broadening of ρ/ω, φ

Several measurements are already done, however, conclusive results are not yet obtained


12 GeV proton induced. p+A → φ + X

Electrons from φ decays are detected.

Spectrometer

15/June/2019 13

R. Muto et al., PRL 98(2007) 042581

Cu

βγ<1.25 (Slow)

e+e- invariant mass

Decays inside nucleusDecays outside nucleus

φmeson has mass modification

Mas modification is shown as an Excess

φmeson has NO mass modification

Blue line shows expected line shape including all experimental effectswo mass modification

Invariant mass spectra of electron-positron pairs in φ meson mass region.


1415/June/2019

Target/Momentum dep.βγ<1.25 (Slow) 1.25<βγ<1.75

Only one momentum bin shows a mass modification under the current statistics.

e+e- invariant mass

Two nuclear targets:Carbon & CopperInside-decay increases in large nucleus

Momentum binSlowly moving φmesons have larger chance to decay inside nucleus

Same as previous slide

Excess



To study finite density medium through mass modifications of vector mesons in nucleus, significantly larger statistics are required Upgrades of the KEK-PS E325 experiment will be conducted at J-PARC Final goal is collecting 100 times larger statistics than the KEK

experiment with an improved mass resolution

φ (1020)

KEK E325 results J-PARC expectation

High StatisticsBetter Resolution

e+e- invariant mass e+e- invariant mass


Measurements of e+e- pair invariant mass spectra in nucleus

10 times larger statistics compared to the KEK experiment 1010 protons per spill (10 times higher than KEK) Counting rate: 5 kHz/mm2 (maximum)

Two times better resolution than KEK Larger magnetic field Better Position resolution (~100 µm)

GEM Tracker

Electron ID

Magnet

We construct new beam line and detectors

17

New Beam Line!

K. Ozawa, ANPhA symposium, Jeju, Korea 15/June/2019

GEM TRACKER


Ionization electrons in the drift gap are collected and amplified by Gas Electron Multiplier (GEM)s. GEM foils are generated by a Japanese

company

Charge collected on to 2D strip readout. X: 350um pitch Sensitive to bending direction. 100 um resolution required.

Y: 1400um pitch

GEM

GEM

GEM

readout

3 mDrift Gap

Mesh electrode

• Timing method• COG method• 2D fit

We have developed a new analysis technique using a timing information for finite incident angle tracks

HADRON BLIND DETECTOR


300x300mm2 GEM with CsI

• Based on PHENIX HBD• Electron identification using gas cherenkov

• CF4 serves as radiator and amplification gas• Radiator 50 cm. / p.e. ~ 11

• Gas Electron Multiplier (GEM) for amplification• CsI is evaporated on top GEM

– Photocathode (> ~6eV)

15/June/2019 20

• Numbers in parenthesis are for βγ <1.25

Condition Target Nφ

RUN 1 160 shifts8 modules

Cu 18100(1900)

RUN 2 320 shifts26 modules

Cu 76000(13700)

E325 Cu 2400(460)

βγ < 1.25

Expected Spectrum with a combinatorial background

(Simulation for Nφ ~ 1000, Run1 )

Yield estimation

A realistic estimation is done with a simulation based on R&D results


We will start data acquisition in 2020 spring


Measurements of ω mesons mass spectra in nucleus at rest When we choose a momentum of the incident beam carefully, we can

generate ω mesons “at rest”. Forward emitted neutron carries momentum of incident beam and

generated ω meson has small momentum

π−A → ω + n+X

π0γ

π

ω π0

n

γReaction:

π- + p (in A) → ω + nWe can measure

π (beam), ω (decays), emitted neutron (Forward detector)The reaction dynamics can be identified by these measurements.

γ

γ


Charmonium (ψ’) Effects of gluon condensates in the matter Significant mass decreasing is suggested Gy. Wolf, G. Balassa, P. Kovács, M. Zétényi, S.H. Lee,Phys. Lett. B780 (2018) 25,

arXiv:1712.06537

Direct measurements using πA reactions and the same spectrometer can be used as pA reactions

D mesons Effects of chiral symmetry restoration to Heavy-Light quark system Probe condensates with light constituent quark (and heavy quark) 20~30 MeV mass “increasing” K. Suzuki, P. Gubler, M. Oka, Phys. Rev. C 93, 045209 (2016) A. Park, P. Gubler, M. Harada, S. H. Lee, C. Nonaka, and, W. Park, Phys. Rev. D 93

054035(2016)

Yield measurements at the threshold region are sensitive to mass modifications


Q

qqCharmed Baryon Charmed baryons have unique internal structures and are suitable to study quark-quark correlations

Excitation states of charmed baryons can be identified as a di-quark motion (λmode) or single charm quark motion (ρmode)

Excitation states can be measured using a missing mass method

ρ

λ

New experiment is proposed. Physics importance of the experiment is already approved. New beam line for vector meson mass measurements will be modified to deliver high momentum secondary beam for this experiment.


Several studies related with nuclear matter is on-going at J-PARC Hypernuclei Kaon bound states

New experiment and new beam line is under construction to measure vector meson mass spectra in nuclei Detector construction is also on-going and we will start the experiment in

2020 spring. Several related experiments are also proposed

J-PARC can probe inside of nucleus using higher energy proton beam and generated secondary beams

As a result, we can perform very comprehensive studies for nucleus, nuclear matter, and high density quark-hadron matter in Asia region!

K. Ozawa (KEK) - INDICO (Indico)...GEM Tracker Electron ID Magnet We construct new beam line and...

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