Transcript Hypernuclear Experimental

Study of Lambda hypernuclei
with electron beams
Satoshi N. Nakamura, Tohoku University
On behalf of
JLab HKS-HES and Hypernuclear
Collaborations
Recent and near-future publications
from HKS-HES collaboration
JLab HKS-HES collaboration, 2009, JLab Hall-C
(Hyper)
Nucleus
Baryon
10
−15
m
Neutron Star
4
10 m
Spectroscopy of Hypernuclei
Obs. 2 M⨀
NN scat.
LQCD
Baryon Interaction
Hyperon Puzzle
s-quark exchange
s,sbar pair creation
(K-,p-)
(p+,K+), (e,e’K+)

Electromagnetic production

Convert Proton
to Lambda :
Isomultiplet partner to well studied HY
by (p,K), (K, p)
Absolute energy calibration
with p(e,e’K+)L, S0

High quality primary beam
High energy resolution (< 1MeV)
Thin enriched
target
Method
Resolution
Absolute E
Yield
comments
(e,e’K+)
0.5 MeV
◎
△ 100nb/sr
𝑝→Λ
(p+,K+)
1.5 – 2 MeV
○ (norm 12LC)
○ 10mb/sr
𝑛→Λ
(K-, p-)
~2 MeV
○ (norm 12LC)
◎ 1 mb/sr
𝑛→Λ
g-ray
0.003 MeV
×
(SA △)
-
Decay p
0.1 MeV
◎ (only g.s.)
(SA ×)
Fragments
E89-009 (2000) : Existing spectrometers,
SOS + Enge
Proof of Principle
E01-011 (2005) :
Construction of HKS, Tilt Method
L, S0, 7LHe, 12LB, 28LAl
Light Hypernuclei
E94-107 (2004-5)
Two HRSs + SC Septum
L, S0,
LLi,
9
LB,
12
LN
16
Light Hypernuclei
E05-115 (2009) :
HKS+HES, new Chicane beamline, Splitter
L, S0, 7LHe , 12LB, 52LV
Light to medium-heavy Hypernuclei
HES
HKS
JLab Hall-A HRS+HRS (2004)
JLab Hall-C
HNSS (2000)
HKS (2005)
HKS+HES (2009)
Mainz MAMI-C A1 KaoS (2008-)
JLab E05-115 (Hall-C) setup
Pre-chicane beam line
θe’ = 6.5 ± 5.0 deg.
7.0 msr
θK = 5.7 ± 4.6 deg.
8.5 msr
Δp/p ~ 2 × 10-4
𝑃𝐾 , 𝑃𝑒′ : 𝑚𝑒𝑎𝑠𝑢𝑟𝑒
𝐸𝑒 , 𝑚𝐴 : 𝑘𝑛𝑜𝑤𝑛
𝑚𝐻𝑌 : 𝑑𝑒𝑑𝑢𝑐𝑒𝑑 𝑎𝑠 𝑀𝑖𝑠𝑠𝑖𝑛𝑔 𝑀𝑎𝑠𝑠
KaoS 2008
JLab E01-011
JLab E05-115
P.Achenbach et al.
JLab E05-115
New measurement of Λ7𝐻𝑒 ground state energy
S.N.Nakamura et al., PRL 110, 012502, (2013).
Triggered active CSB discussion
Detailed 12
Λ𝐵 spectroscopy with the best resolution (FWHM~0.5 MeV)
New measurement of 10
Λ𝐵𝑒 spectroscopy
L.Tang et al., PRC 90, 034320, (2014).
T.Gogami et al., to be submitted soon
Small CSB for A>=7 hypernuclei
Indication of possible shift of 12
Λ𝐶 ground state energy : Absolute calibration
+
New measurement of 28
Λ𝐴𝑙 spectroscopy : first beyond p-shell HY by (e,e’K )
C.Chen et al., preparing draft
Information about L’s single particle potential
T.Gogami et al. NIM A729 (2013) 816.
Y.Fujii et al. NIM A795 (2015) 351.
7
Λ𝐻𝑒
excited state paper and another NIM will follow.
Charge Symmetry Breaking
Effect of the LN interaction
BL (L4 H,1 )  1.00  0.06 MeV
1
BL (L4 He,1 )  1.24  0.06 MeV
0.24 MeV
BL (L4 H,0 )  2.04  0.04 MeV
LH
4
L
n
n
p
0.35 MeV
0
BL (L4 He,0 )  2.39  0.03 MeV
L
n
p
p
LHe
4
Coulomb effect is small.
Charge Symmetry Breaking
cf) B(3H)-B(3He)-DBc = 764-693 = 71 keV
S
N
LS mass difference ~ 80 MeV
L
<
N
ND mass difference ~ 300MeV
M(S) < M(S0) < M(S-),
DM(S--S)~8MeV
Modern ChPT-NLO calculation predicts 3NF effect is < 100keV but
NLO calculation cannot explain experimental results for A=4, T=1/2, hypernuclei.
(Nogga, HYP2012)
Consistent understanding of 0+, 1+ of
Phenomenological potential :
A.R.Bodmer&Q.N.Usmani, PRC 31(1985)1400.
4
4
LH, LHe
No reported BL
LHe
7
LH
4
B ( H )  2.04  0.04 MeV
4
L L
L
n
L
LLi*
LHe
4
p
BL ( L4 He)  2.39  0.03 MeV
L
n
p
7
L L
L
n
LBe
a p
Hiyama et al. PRC 80.054321
PTP 128 (2012) 105..
3 event
a
a
LB
10
BL (10L B)  8.89  0.12 MeV
L
p
n
167 events
BL ( L7 Be)  5.16  0.08 MeV
7
DCSB
L
*
98 events
p
Experimental BL
BL ( L7 Li* )  9.11  0.22 MeV
B ( Li )  5.26  0.03 MeV
7
n
LBe
10
a n
n
67 events
Exp. Data : Emulsion
a p
15 events
L
p
a
a
10 events
L behaves like glue
6He
: 2n halo
E.Hiyama et al.
PRC 80, 054321 (2009)
SNN et al., PRL 110, 012502 (2013)
E01-011
(2005)
Assumed CSB potential may be too naïve.
New measurements on A=4 systems are necessary.
E05-115
(2009)
T.Gogami, Doctor Thesis (2014) Tohoku Univ.
CSB interaction test in A=7 isotriplet comparison
EΛ (3/2+,5/2+) [MeV]
E.Hiyama et al.,
PRC 80, 054321 (2009)
M.Sotona et al.,
PTP 117 (1994)
D.J.Millener
Private Comm. (2013)
1.70
E01-011
(2005) 1.79
1.72
E05-115
(2009)
T.Gogami, Doctor Thesis (2014) Tohoku Univ.
0.54 MeV (FWHM)
Absolute MM calibration
0.71 MeV (FWHM)
L.Tang, C.Chen, T.Gogami et al.
Phys. Rev. C 90 (2014) 034320.
12C(π+,K+)12 C
Λ
1.45 MeV (FWHM)
LCgs
12
energy
from emulsion
KEK-PS
E369
11C
Statistical error only
(3/2-) : Ex = 4.8MeV
Reference for all (p, K) BL data:
BL (12LCg.s.) = 10.76 +-0.19MeV
(# of events)
BL (12LBg.s.) = 11.45 +-0.07 MeV
Emulsion Result (M.Juric et al.)
BL (12LBg.s.) = 11.38 +- 0.02 (stat) MeV (JLab E05-115)
Totally independent measurement
BL(emulsion)-BL (p,K) [MeV]
The difference of the same values measured by different methods.
If 12
Λ𝐶 gs. measured by emulsion is shifted by 0.54 MeV,
all data are consistent and CSB for A=12 is zero.
+
12
ΛC
Possible
gs shift of
0.54MeV
Small CSB
Only accessible by the 4He(e,e’K+)4LH at JLab
BL ( L4 H,1 )  New data necessary
1
g-ray : level spacing
Decay p: ground state
0.16 MeV
Mainz New data :
PRL 114, 232501 (2015)
BL ( L4 H,0 )  2.12  0.09 MeV
L
n
n
p
0.27 MeV
J-PARC E13 (g-ray; hyperball)
has successfully
measured!
0
L
n
p
p
Cutoff of potential in coupled channel LS equation based on Ch EFT vs. BL(4LH).
J. Haidenbauer, JLab Hypernuclear WS, May 2014
2.12 ± 0.02 ± 0.09 𝑀𝑒𝑉
Recently re-measured at Mainz (PRL 114.232501, 2015)
Measureable with the
(e,e’K) reaction at JLab
Existing experimental uncertainty may be larger. Since CSB term is not
consistently understood for A=4 and A=7 hypernuclei.
CSB potential is too naïve or A=4 data have problem.
LH
4
data indicate : LO Ch EFT depends much on cut-off parameter (especially 1+).
NLO looks underbind 4LH
Long range 3BFs need to be estimated
with reliable experimental inputs
N2LO
s
p
d
JLab E01-011
T.Motoba, JLab Hypernuclear WS (2014)
peak
BL (MeV)
s
-16.54
p
-8.47
d
-1.08
K(HKS) x HRS (e’)
Only JLab : Beam + Spectrometers for (e,e’K+)
Advantage of the proposed setup over previous experiments.
Higher Pe’ with HRS
Excellent momentum resolution (2x10-4)
Orbit is long but no problem for e’
Established in Hall-A
Allow to use higher (4.5 GeV) incoming electron beam.
Background from Bremsstrahlung will be boosted to forward.
Introduction of Septum magnet
Easier and more reliable calibration of HKS-HRS systems separately.
Good Signal to Noise ratio
Electron BG will be 1/40 of Hall-C exps.
HKS
Established in Hall-C
Excellent momentum resolution (2x10-4) with short orbit to avoid decay loss of
kaons with lower momentum (1.2 GeV/c).
Large solid angle as well as momentum acceptance.
High resolution
Large Yield (best virtual photon energy & HKS acceptance)
Keep resolution and 5.4 times larger yield than Hall-A exp.
YN interaction
Charge Sym. Breaking
Part I.
Light Hyp.Nucl.
4 H
L
spectroscopy
p(e,e’K+)L, S0
Exotic systems ([nL],[nnL])
Established lightest HY (3LH)
Hyperon puzzle
in neutron stars
Part II.
Mid-Heavy Hyp.Nucl.
A dependence of BL
(40LK, 89LSc, 208LTl)
Isospin dependence
(40LK, 48LK)
Conditionally Approved (C2) by PAC43
(2011)
(2014)
LV
52
6
LH
Updated from: O. Hashimoto and H. Tamura, Prog. Part. Nucl. Phys. 57 (2006) 564.




We have been developing large magnetic spectrometers
(HKS, HES) and techniques in the last decade at JLab and
(e,e’K+) HY spectroscopy is now established.
Best spectroscopy of 12LB was performed and absolute
binding energy calibration implies a shift (500-600 keV) of
12 C emulsion B which is the reference to all (p,K)
L
L
spectrosopy binding energies.
Binding energy of 7LHegs was determined. Important
input for LN CSB potential. Excited state of 7LHe was
clearly observed.
New spectroscopy on 10LBe and 28LAl
Hypernuclear spectroscopy with electron beam is unique and quite
effective way to investigate the baryon interaction.
Currently only JLab can perform (e,e’K+) spectroscopy.
Combined with decay p at Mainz, g-ray spectroscopy at J-PARC,
CSB and EoS of NS should be studied in timely manner.