baryon spectroscopy with secondary hadronic beams at...
TRANSCRIPT
Baryon spectroscopy with secondary hadronic beams
at J-PARC
K. Shirotori for the E50/E31 collaboration
Research Center for Nuclear Physics (RCNP)
Osaka University
International symposium on Clustering as a Window
on the Hierarchical Structure of Quantum Systems (CLUSHIQ2020)
23rd January 2020
Contents
• Motivations
• Study of excited states: Effective degree of freedoms of hadron
• Spectroscopy of charmed baryon and hyperon at J-PARC
• High-p beam line and multi-purpose spectrometer
• Study of hadron molecule state: L(1405)
• J-PARC E31 experiment
• Summary
2
Motivations
Investigations of excited states
Charmed baryon and hyperon spectroscopy
How hadrons are originated by quark and gluon ?
• Understand hadrons
by new effective degree of freedom
⇒ Semi-Hierarchies
between Hadron and Quark・Gluon (A02)
＊J-PARC & LEPS2 projects
4
q
q
q
q-q
q
Conventional
HierarchiesSemi-Hierarchies
• Constituent quark
• Diquark
• Hadron molecule
Diquark Hadron molecule
q
Excited states: Observation of exotic hadrons
＊Excited states: Rich properties
⇒Mass, width, decay branching ratio, spin and parity
from new effective degree of freedoms extended to ordinary constituent quark model
5
Constituentquark
q
q
q
Exotic hadronsq
q
q
Meson Baryon
Hadron molecule Multi-quark
q
q q
Excited states: Observation of exotic hadrons6
q
q
q
q
q
q
Meson Baryon
Hadron molecule
q-q
q
Diquark correlation &
Hadron molecule
Diquark
correlation
Multi quark
q
q q
qqExotic hadrons
Constituentquark
Excited states and effective degree of freedoms7
• Properties of excited states ? (Mass, G, JP)
• Role of effective degree of freedoms ? (Systematics)
• How (where) configurations emerge ? (Threshold region …)
• Understand whole hadron properties universally ?
3q baryon Meson baryon
(Molecule)
Pentaquark
(Multi quark)
Excited states and effective degree of freedoms8
• Properties of excited states ? (Mass, G, JP)
• Role of effective degree of freedoms ? (Systematics)
• How (where) configurations emerge ? (Threshold region …)
• Understand whole hadron properties universally ?
3q baryon Meson baryon
(Molecule)
Pentaquark
(Multi quark)
Excited states with heavy quark: Diquark9
“Excited mode”: l and r modes in heavy baryon excited states (q-q + Q system)
⇒ Diquark correlation: q-q isolated and developed
Q
q-q
Q
q-q
q
l modeCorrective motion
btw q-q and Q
G.S.
Excited states
by spin-spin
interaction
⇒ Observables
Light quark baryon
r modeExcitation of q-q
Excited states with heavy quark: Diquark10
“Excited mode”: l and r modes in charmed baryon excited states (q-q + system)
⇒ Diquark correlation from Production rate and Decay branching ratio
c
q-q
c
q-q
q
l modeCorrective motion
btw q-q and Q
G.S.
Excited states
by spin-spin
interaction
⇒ Observables
Light quark baryon
r modeExcitation of q-q
Charmed baryon spectroscopy experiment: J-PARC E50
＊p- + p → Yc*+ + D*- reaction @ 20 GeV/c
• High-intensity p- beam: 6.0×107 /spill
• Production rates & Decay branching ratios
Production rates by hadronic reaction11
• p- + p → Yc*+ + D*- reaction: Missing mass method
＊Production rates ⇔ Internal structure of excited states
⇒ Selective production of corrective motion: l mode
＊Angular momentum transfer between
diquark (q-q) and charm quark
Reaction diagram
Lc@
1 n
b
Lc(
25
95)
Lc(
2625)
Sc(
28
00)
Lc(
29
40
)
Sc(
24
55
)
Sc(
25
20
)
Lc(
288
0)
Simulation
S.H. Kim, A. Hosaka, H.C. Kim, H. Noumi, K. Shirotori
Prog. Theor. Exp. Phys. 103D01 (2014).
iefff rqiR )exp(2 ~
-
＊Production cross section
⇒ Overlap of wave function
＊charm and q-q (spectator)
1 : 2 3 : 2
Decay property
• Decay measurement: GpSc⇔ GND• p-+ Sc
++, p+ + Sc0
• p + D0
⇒Absolute value of branching ratio by missing mass method• Compliment study with high-energy experiments
12
r-mode decay: qqQ + qqbar l-mode decay: qqq + Qqbar
qqQ
qqq
p
Sc
N
D
GpSc > GND GpSc < GND
Spectroscopy with heavy quark13
• Clear distinction by separating effects from one quark
• Systematic study
• Charmed baryon spectroscopy: To understand role of diquark correlation
• Dynamical information: Production rates & Decay branching ratios
Production Decay
qqq
N
D
GpSc < GND
Excitation spectrum: q-q + Q system14
Strange baryons
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 [MeV/c2]
Sc(1/2+)
Lc(1/2+)
Sc*(3/2+)
Lc(1/2-, 3/2-)
Lc(1/2-, 3/2-, 5/2-)
l
r
r
L(1/2-, 3/2-, 5/2-)
S(1/2+)
L(1/2+)
S*(3/2+)
Charmed baryonsP-wave states
s c
L(1/2-, 3/2-)
L(1/2-, 3/2-)Lc(1/2-, 3/2-)
• Non-rel. QM: H = H0 + Vconf + VSS + VLS + VT
• l-r mixing
(cal. By T. Yoshida et al., Phys. Rev. D92 , 114029(2015)
＊Diquark correlation: l & r
・Heavy quark sector (charm)
⇒ Light quark sectors (u, d, s)
b
Excitation spectrum: q-q + Q system15
Strange baryons
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 [MeV/c2]
Sc(2455, 1/2+)
Lc(2286, 1/2+)
Sc*(2520, 3/2+)
Lc(2595, 1/2-)
Lc(2940, ?)
l
r
r
L(1830, 5/2-)
S(1190, 1/2+)
L(1116, 1/2+)
S*(1385, 3/2+)
Charmed baryonsP-wave states
s c
L(1520, 3/2-)
L(1670, 1/2-)Lc(2880, 5/2+)
• Non-rel. QM: H = H0 + Vconf + VSS + VLS + VT
• l-r mixing
(cal. By T. Yoshida et al., Phys. Rev. D92 , 114029(2015)
L(1405, 1/2-)
L(1690, ?)
Lc(2625, 3/2-)
Lc(2765, ?)
＊Diquark correlation: l & r
・Heavy quark sector (charm)
⇒ Light quark sectors (u, d, s)
b
Strange baryon systems
• L* /S* : q-q + Q system
⇒ Systematics with charmed baryon• Production rate: l and r selection• Decay branching ratio
• X* : q + QQ system
⇒ Excitation with two heavy quarks• Interchange of l and r modes
• W* : QQQ system
⇒ Same weight of three heavy quarks
＊Spectroscopy by high-momentum K- beam• Several GeV/c beam• Poor data of X and W states• Exotic states
⇒ Systematic measurement is necessary.
16
Q
q-q
q
Q Q
Q
X*
W*
L*/S*
High-momentum beam line for 2ndary beam
• High-intensity beam: > 107 Hz p (> 105 Hz K/pbar) up to 20 GeV/c• Unseparated beam: p/K/pbar
• High-resolution beam: Dp/p ~ 0.1%(rms)• Momentum dispersive optics method
17
Collimator
Production Target
(SM)
Exp. Target (FF)
Focal Point (IF)
Charmed baryon spectrometer18
2m
LH2-target
Beam p-
p-
K+
ps- Ring Image
Cherenkov
Counter
DC
TOF wall
PID counter
Fiber tracker
T0
Pole face
detector
Internal DC
Internal TOF
Fiber wall
p-
p+
19
2m
LH2-target
Beam p-
p-
K+
ps- Ring Image
Cherenkov
Counter
DC
TOF wall
PID counter
Fiber tracker
T0
Pole face
detector
Internal DC
Internal TOF
Fiber wall
p-
p+
Resistive Plate Chamber (RPC)
Scintillation fiber tracker Barrel Drift Chamber
RICHBeam RICH
Cherenkov timing detector
20
2m
LH2-target
Beam p-
p-
K+
ps- Ring Image
Cherenkov
Counter
DC
TOF wall
PID counter
Fiber tracker
T0
Pole face
detector
Internal DC
Internal TOF
Fiber wall
p-
p+
Resistive Plate Chamber (RPC)
Scintillation fiber tracker Barrel Drift Chamber
RICHBeam RICH
Cherenkov timing detector
Large Acceptance Multi-Purpose Spectrometer
+ Trigger–less DAQ system
Charmed baryon spectrometer
⇒ New platform for Hadron experiment
Hadron molecular state
Study of L(1405)
J-PARC E31 experiment at K1.8BR
Λ(1405): Lightest in negative parity baryons
＊ JP = 1/2-, I = 0, ML(1405)< MKbarN
22
KbarNpS
D. Jido et al., NPA725, 181 (2003)
PRL114, 132002 (2015)
LQCD: KbarN molecule
L(1116), 1/2+
L(1405), 1/2-
L(1520), 3/2-
S*(1385), 3/2+
S(1192), 1/2+
KN(1432)
-27 MeV
＊Chiral Unitary Model
⇒ Double pole structure
・KbarN & pS
KbarN scattering below the KbarN threshold
• S-wave KbarN→πΣ scattering below the KbarN threshold
• d(K-,n)pS at a forward angle of n: 1 GeV/c K- beam
⇒ Decomposition of all I = 0 and 1 amplitudes
23
n
K-
p
p-
d target
K- d nL(1405)
Sp
Reaction diagram
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
Reaction
Detector image
Experimental results: Cross section of pS modes24
𝒅𝝈
𝒅𝜴𝝅𝟎𝜮𝟎 ∝
𝟏
𝟑𝒇𝑰=𝟎
𝟐
0
5
10
15
20
25
30
1350 1400 1450 1500
[𝝅±𝜮∓ − 𝝅−𝜮𝟎]/𝟐
𝑲−𝒑𝝅𝟎𝜮𝟎
𝒅𝝈
𝒅𝜴[𝝅±𝜮∓ − 𝝅−𝜮𝟎]/𝟐 ∝
𝟏
𝟑𝒇𝑰=𝟎
𝟐
𝝅±𝜮∓ − 𝝅−𝜮𝟎
𝟐𝐯𝐬 𝝅𝟎𝜮𝟎(𝑰 = 𝟎)
Cross sections of each pS mode
＊I = 0 amplitude seems dominant.
Preliminary PreliminaryPreliminary
25
𝒅𝝈
𝒅𝑴𝝅𝜮ቚ𝜽𝒏=𝟎
~ 𝑻𝟐𝑰 (ഥ𝑲𝑵 → 𝝅𝚺)
𝟐𝑭𝒓𝒆𝒔(𝑴𝝅𝜮)
To deduce scattering amplitude and extract pole position
Pole at (𝟏𝟒𝟏𝟕−𝟕+𝟔 − 𝒊𝟐𝟕−𝟗
+𝟓 ) MeV/c2
＊Seems consistent with higher pole by the Chiral Unitary Model based calculations
Preliminary
Related subjects and experiments
• High-p beam line: Beam delivered from 2020 February !• Measurement of mass modification of f meson: J-PARC E16
⇒ 2ndary beam line and heavy baryon spectroscopy (charm, X&W)
• Studies of L(1405)• K- beam @ J-PARC: Production angle dependence• High-p beam @ J-PARC: Quark counting rule• g beam @ LEPS2: Polarized beam
• K-pp state• Deeply bound state due to help by strong attraction of KbarN(L(1405))• Production by K- and g beam: Experiments are planned at J-PARC & LEPS2.
• H-Dibaryon search: J-PARC E42• By (K-, K+) reaction on nuclear target
• p N → p p N experiment: J-PARC E45• Basics data for N*/D* resonances
26
＊Hadron spectroscopy
By Hadronic beams @ J-PARC
and Photon beam @ LEPS, ELPH
Summary• Motivations
• Study of excited states: Effective degree of freedoms of hadron• Diquark correlation and hadron molecular
• Spectroscopy of charmed baryon and hyperon at J-PARC• To understand role of diquark correlation by dynamical information: Production rates & Decay branching ratios
• Systematic measurement: Charm, strangeness = -1, -2, -3
• High-p beam line and multi-purpose spectrometer• Beam line from Feb. 2020 ⇒ 2ndary beam for hadron spectroscopy• Spectrometer system for many physics reactions: Trigger-less DAQ
• Study of hadron molecule state: L(1405)• Cross section of all pS modes⇒ KbarN scattering amplitude to extract pole⇒ (𝟏𝟒𝟏𝟕−𝟕
+𝟔 − 𝒊𝟐𝟕−𝟗+𝟓 ) MeV/c2
• Related studies for hadron physics＊Hadronic and photon beams @ J-PARC, LEPS, ELPH
27