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M. Iwasaki
for E15 collaboration
Kaonic nuclear state search by kaon reaction on 3He
target at 1 GeV/c
11
MIN16 - Meson in Nucleus 2016, 31 Jul - 2 Aug
- Can kaon be a member of nuclei?- Kaon properties change in nuclear media?
ObjectivesKey questions :
χ-condensateNon-perturbative aspects @ energy < ΛQCD Finite density → sign problem Lattice-QCD approach difficult
Hadron masses and χ-symmetry
2
Search for Kaonic nuclear states
nuclear state search
3He(K-, n) @ 1 GeV/c
strongly attractive in I=0 channel
formation of high density matter?
K-pp• simplest system
BK ~ 50 MeV!
assuming Λ(1405) = K-p bound state …T. Yamazaki & Y. Akaishi, PLB 535 (2002) 70
3
T.Yamaga
◆ Recentresults
4
E-indep.
Reportsstructure /NOstructure
►Experiments►Theoreticalcalc.
KNinteractionmodelE-dep./E-indep.
J-PARC E15 1st
?
3He(K-, Λp)n:
with single pole assumption
Kpp should be studied moreE-dep.
5
Mðp!Þ # 2255 MeV=c2 of the K$pp candidate reportedby FINUDA [16].
The X production rate is found to be as much as the!ð1405Þð¼ !&Þ production rate, which is roughly 20% ofthe total ! production rate. Such a large formation istheoretically possible only when the p-p (or !&-p) rmsdistance in X is shorter than 1.7 fm [3,4], whereas theaverage N-N distance in ordinary nuclei is 2.2 fm. Thepp ! !& þ pþ Kþ ! Xþ Kþ reaction produces !&and p of large momenta, which can match the internalmomenta of the off-shell !& and p particles in the boundstate of X ¼ !&-p, only if X exists as a dense object. Thus,the dominance of the formation of the observed X at high
momentum transfer (#1:6 GeV=c) gives direct evidencefor its compactness of the produced K$pp cluster.As shown in Fig. 4, the peak is located nearly at the "!
emission threshold, below which the N"! decay is notallowed. The expected partial width of K$pp, #N"!, mustbe much smaller than the predicted value of 60 MeV [2],when we take into account the pionic emission thresholdrealistically by a Kapur-Peierls procedure (see [20]). Thus,#non-! ¼ #p! þ #N" ¼ #obs $ #N"! ( 100 MeV, whichis much larger than recently calculated nonpionic widthsfor the normal nuclear density, #non-! # 20–30 MeV[7,21]. The observed enhancement of #non-! roughly by afactor of 3 seems to be understood with the compact natureof K$pp [4].The observed mass of X corresponds to a binding energy
BK ¼ 103) 3ðstatÞ ) 5ðsystÞ MeV for X ¼ K$pp. It islarger than the original prediction [2,8,9]. It could beaccounted for if the $KN interaction is effectively enhancedby 25%, thus suggesting additional effects to be investi-gated [4,22]. On the other hand, the theoretical claims forshallow $K binding [10–12] do not seem to be in agreementwith the observation. We emphasize that the deeply boundand compact K$pp indicated from the present study is animportant gateway toward cold and dense kaonic nuclearmatter [15,23].We are indebted to the stimulating discussion of
Professors Y. Akaishi and R. S. Hayano. This researchwas partly supported by the DFG cluster of excellence‘‘Origin and Structure of the Universe’’ of TechnischeUniversität München and by Grant-in-Aid for ScientificResearch of Monbu-Kagakusho of Japan. One of us (T. Y.)acknowledges the support of the Alexander von HumboldtFoundation, Germany.
[1] Y. Akaishi and T. Yamazaki, Phys. Rev. C 65, 044005(2002).
[2] T. Yamazaki and Y. Akaishi, Phys. Lett. B 535, 70 (2002).[3] T. Yamazaki and Y. Akaishi, Proc. Jpn. Acad. Ser. B 83,
144 (2007); arXiv:0706.3651v2.[4] T. Yamazaki and Y. Akaishi, Phys. Rev. C 76, 045201
(2007).[5] T. Yamazaki et al., Hyperfine Interact. 193, 181 (2009).[6] M. Maggiora et al., Nucl. Phys. A835, 43 (2010).[7] M. Faber, A. N. Ivanov, P. Kienle, J. Marton, and M.
Pitschmann, arXiv:0912.2084v1.[8] N. V. Shevchenko, A. Gal, and J. Mares, Phys. Rev. Lett.
98, 082301 (2007); N.V. Shevchenko, A. Gal, J. Mares,and J. Révai, Phys. Rev. C 76, 044004 (2007).
[9] Y. Ikeda and T. Sato, Phys. Rev. C 76, 035203 (2007).[10] D. Jido, J. A. Oller, E. Oset, A. Ramos, and U.-G.
Meissner, Nucl. Phys. A725, 181 (2003); V. K. Magas,E. Oset, and A. Ramos, Phys. Rev. Lett. 95, 052301(2005).
[11] T. Hyodo and W. Weise, Phys. Rev. C 77, 035204 (2008).[12] A. Doté, T. Hyodo, and W. Weise, Phys. Rev. C 79,
014003 (2009).
0
0.5
1.0
1.5
2.0
2.5
2150 2200 2250 2300 2350 2400 2450
2150 2200 2250 2300 2350 2400 2450
200 100 0
0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
(a) large-angle proton: high-P (p)
(b) small-angle proton: low-P (p)
Γ = 118 (8)
M = 2267 (2)
M = 2267 (2)
Missing Mass ∆M(K) [MeV/c ]2
Missing Mass ∆M(K) [MeV/c ]2
M(Λ
*+p)
= 2
345
M(Λ
*+p)
= 2
345
M(K
+p+p
) = 2
370
M(K
+p+p
) = 2
370
M(Σ
+π+p
) =
2267
M(Σ
+π+p
) = 2
267
Dev
iatio
nU
NC
/SIM
(arb
. sca
le)
Dev
iatio
nU
NC
/SIM
(arb
. sca
le)
B (K pp) [MeV]-
T
T
FIG. 4 (color online). (a) Observed DEV spectra of %MðKþÞof events with LAP emission [j cos"cmðpÞj< 0:6] and (b) withSAP emission [j cos"cmðpÞj> 0:6]. Both selected with large-angle Kþ emission [$ 0:2< cos"cmðKþÞ< 0:4].
PRL 104, 132502 (2010) P HY S I CA L R EV I EW LE T T E R Sweek ending2 APRIL 2010
132502-4
DISTO
present “Kpp" candidates @ BK~100 MeVhyper deep ??
Many objections exist, though…
J-PARK E27
M(Σ+π+p)
why no threshold (Σπp) effect seen?why no quasi-elastic K seen?
…p + p → p + N+(1710) → p + (Λ +K+)
→ (p + Λ) + K+ ??
M(K+p+p)
PublishedE151stdata
3He(K-,n)—semi-inclusive
3He(K-,Λp)n—exclusive
Only3days!(suspendedbytheearthquake)
6
PublishedE151stdata
3He(K-,n)—semi-inclusive
3He(K-,Λp)n—exclusive
Only3days!(suspendedbytheearthquake)
6withnewdata!
qK ~ 200 MeV/c
qK ~ 200 MeV/c
analyzedonlykinematically
AssumingaBreit-Wigner
8
• χ2-testwithpole&3NA(Ypn)– S-waveBreit-Wignerpole– w/Gaussianform-factor
B(X) ~ 15 MeVΓ(X) ~ 110 MeVQ(X) ~ 400 MeV/c
MΛp→
qΛp
→
9
Lorentzinvariantphase-space
Breit-Wigner
– introducesimplestassumptionS-wavepole&Breit-Wignerformula&Gaussianform-factor
form-factor2
stickingprobabilitytoharmonicoscillator
Assumingsinglepole(Breit-Wigner)
B(X) ~ 15 MeV, Γ(X) ~ 110 MeV, Q(X) ~ 400 MeV/c
ImprovingstatisticsviaE152nddataWhatisthestructurefoundinE151stdata?
~30timesmoredataforΛpnfinalstate
~6timesmoredataforforwardneutron
3days→3weeksw/higherprioritytoΛpinCDSE151st E152nd
MΛp→
Very Preliminary
11]2 [GeV/cM Λpinv.2 2.1 2.2 2.3 2.4 2.5 2.6 2.7 2.8 2.9 3
0
5
10
15
20
Cou
nts
per 2
0 MeV
/c2
data
sum
Multi-NA sum (w/o pole)
Λp invariant massM(K-+p+p)M(
M(Σ+π)Λ(1405)+p)
(x5)
E151standE152ndspectraconsistent?
MΛp→
]2 [GeV/cM Λpinv.2 2.1 2.2 2.3 2.4 2.5 2.6 2.7 2.8 2.9 30
5
10
15
20
Cou
nts
per 2
0 MeV
/c2
Λp invariant massM(K-+p+p)M(
M(Σ+π)Λ(1405)+p)
E15 1st
12
E151standE152ndspectraconsistent?
MΛp→
200
Cou
nts
per 1
0 MeV
/c2 E15 2nd
0
100
300
]2 [GeV/cM Λpinv.2 2.1 2.2 2.3 2.4 2.5 2.6 2.7 2.8 2.9 3
Λp invariant massM(K-+p+p)M(
M(Σ+π)Λ(1405)+p)
E15 1st
13
Very Preliminary
YES!Theyareconsistent!
E151standE152ndspectraconsistent?
MΛp→
14
200
Cou
nts
per 1
0 MeV
/c2 E15 2nd
0
100
300
]2 [GeV/cM Λpinv.2 2.1 2.2 2.3 2.4 2.5 2.6 2.7 2.8 2.9 3
Λp invariant massM(K-+p+p)M(
M(Σ+π)Λ(1405)+p)
E15 1st
E152ndspectrumdoesnotallowsinglepoleassumptionlooks like trapezoidal??
E151standE152ndspectraconsistent?YES!Theyareconsistent!
need further study
Very PreliminaryMΛp→
T.Yamaga
MENU2016@Kyoto
Inefficientregion Inefficientregion
15
KinematicalLimit
kinematical limitK-pp formation
ns
ps 2NA processwith spectatorns / ps
flat for point-like 3NACM
Is 3He point-like?
T.Yamaga
MENU2016@Kyoto
16
2NA
structure(s?)
PRELIMINARY
K- +“pp+ns”→Λp+ns
Λp invariant massVery Preliminary
MΛp→
3He(K-, Λp)n: Angular Dependence of n in CM
3He(K-, Λp)n: Angular Dependence
0.0
0.5
1.0
ccoossnnθθ(CM)
2.0 2.2 2.4 2.6 2.8 3.0[GeV/c2]ΛΛp.Minv
forward n only
Very PreliminaryqΛp→
MΛp→
3He(K-, Λp)n: Angular Dependence
0.0
0.5
1.0
ccoossnnθθ(CM)
2.0 2.2 2.4 2.6 2.8 3.0[GeV/c2]ΛΛp.Minv
countsper20MeV/c2
2.0 2.2 2.4 2.6 2.8 3.0[GeV/c2]ΛΛp.Minv
0
20
40
60
80
100
3He(K-, Λp)n: Angular Dependence
0.0
0.5
1.0
ccoossnnθθ(CM)
2.0 2.2 2.4 2.6 2.8 3.0[GeV/c2]ΛΛp.Minv
countsper20MeV/c2
2.0 2.2 2.4 2.6 2.8 3.0[GeV/c2]ΛΛp.Minv
0
20
40
60
80
100
0.0
0.5
1.0
ccoossnnθθ(CM)
2.0 2.2 2.4 2.6 2.8 3.0[GeV/c2]ΛΛp.Minv
M(
++p
)
M(K
+p+p
)
2.0 2.2 2.4 2.6 2.8 3.0[GeV/c 2]p.Minv
0
50
100
150
200
250 !"!#$%%&%$'(!"!)*+
coun
ts p
er 2
0 M
eV/c
2
nwindow = 0.85 - 1.03 GeV/c 2
(CM)
countsper20MeV/c2
2.0 2.2 2.4 2.6 2.8 3.0[GeV/c2]ΛΛp.Minv
0
20
40
60
80
100
3He(K-, Λp)n: Angular Dependence of n in CM
in more detailas a clue to understand
3He(K-, Λp)n: Angular Dependence
0.0
0.5
1.0
ccoossnnθθ(CM)
2.0 2.2 2.4 2.6 2.8 3.0[GeV/c2]ΛΛp.Minv
coun
ts p
er 2
0 M
eV/c
2
0
20
40
60
80
100
120
140 !"!#$%$%#!"!'()
M(K
+p+p
)
M(
++p
)
*
2.0 2.2 2.4 2.6 2.8 3.0[GeV/c 2]p.Minv
(CM)
nwindow = 0.85 - 1.03 GeV/c 2
Very Preliminary
3He(K-, Λp)n: Angular Dependence
0.0
0.5
1.0
ccoossnnθθ(CM)
2.0 2.2 2.4 2.6 2.8 3.0[GeV/c2]ΛΛp.Minv
coun
ts p
er 2
0 M
eV/c
2
0
20
40
60
80
100
120
140 !"!#$%##$&'!"!()*
M(K
+p+p
)
M(
++p
)
+
2.0 2.2 2.4 2.6 2.8 3.0[GeV/c 2]p.Minv
(CM)
nwindow = 0.85 - 1.03 GeV/c 2
Very Preliminary
3He(K-, Λp)n: Angular Dependence
0.0
0.5
1.0
ccoossnnθθ(CM)
2.0 2.2 2.4 2.6 2.8 3.0[GeV/c2]ΛΛp.Minv
coun
ts p
er 2
0 M
eV/c
2
0
20
40
60
80
100
120
140 !"!#$%$%#!"!'()
M(K
+p+p
)
M(
++p
)
*
2.0 2.2 2.4 2.6 2.8 3.0[GeV/c 2]p.Minv
(CM)
nwindow = 0.85 - 1.03 GeV/c 2
Very Preliminary
3He(K-, Λp)n: Angular Dependence
0.0
0.5
1.0
ccoossnnθθ(CM)
2.0 2.2 2.4 2.6 2.8 3.0[GeV/c2]ΛΛp.Minv
coun
ts p
er 2
0 M
eV/c
2
0
20
40
60
80
100
120
140 !"!#$%##$&'!"!()*
M(K
+p+p
)
M(
++p
)
+
2.0 2.2 2.4 2.6 2.8 3.0[GeV/c 2]p.Minv
(CM)
nwindow = 0.85 - 1.03 GeV/c 2
Very Preliminary
3He(K-, Λp)n: Angular Dependence
0.0
0.5
1.0
ccoossnnθθ(CM)
2.0 2.2 2.4 2.6 2.8 3.0[GeV/c2]ΛΛp.Minv
coun
ts p
er 2
0 M
eV/c
2
0
20
40
60
80
100
120
140 !"!#$%$%#!"!'()
M(K
+p+p
)
M(
++p
)
*
2.0 2.2 2.4 2.6 2.8 3.0[GeV/c 2]p.Minv
(CM)
nwindow = 0.85 - 1.03 GeV/c 2
Very Preliminary
3He(K-, Λp)n: Angular Dependence
0.0
0.5
1.0
ccoossnnθθ(CM)
2.0 2.2 2.4 2.6 2.8 3.0[GeV/c2]ΛΛp.Minv
coun
ts p
er 2
0 M
eV/c
2
0
20
40
60
80
100
120
140 !"!#$%%%$&'!"!()*
M(K
+p+p
)
M(
++p
)
+
2.0 2.2 2.4 2.6 2.8 3.0[GeV/c 2]p.Minv
(CM)
nwindow = 0.85 - 1.03 GeV/c 2
Very Preliminary
typical momentum transfer QK 400MeV/c~
3He(K-, Λp)n: Angular Dependence of n in CM
two components exist?
bound region : forward peaking
weakly depend to cosθS-wave would be OK
unbound region :
very forward peaking
lower QK preferredbit strongly depend to cosθ
if that is the case,
Structure can be explained with quasi-elastic K scattering?
3He(K-, Λp)n:Not like semi-inclusive spectrum,
“quasi-free K” excluded by the final state: Λpn,
but still need to ask …
through uncorrelated Λ(1405)p channelSekihara Oset Ramos
3He(K-, Λp)n:
0.0
0.5
1.0
ccoossnnθθ(CM)
2.0 2.2 2.4 2.6 2.8 3.0[GeV/c2]ΛΛp.Minv
M(
++p
)
M(K
+p+p
)
2.0 2.2 2.4 2.6 2.8 3.0[GeV/c 2]p.Minv
0
50
100
150
200
250 !"!#$%%&%$'(!"!)*+
coun
ts p
er 2
0 M
eV/c
2
nwindow = 0.85 - 1.03 GeV/c 2
(CM)
countsper20MeV/c2
2.0 2.2 2.4 2.6 2.8 3.0[GeV/c2]ΛΛp.Minv
0
20
40
60
80
100
0.0
0.5
1.0
ccoossnnθθ(CM)
2.0 2.2 2.4 2.6 2.8 3.0[GeV/c2]ΛΛp.Minv
3He(K-, Λp)n: Quasi-elastic?
simple QE?M
(+
+p)
M(K
+p+p
)
2.0 2.2 2.4 2.6 2.8 3.0[GeV/c 2]p.Minv
0
50
100
150
200
250 !"!#$%%&%$'(!"!)*+
coun
ts p
er 2
0 M
eV/c
2
nwindow = 0.85 - 1.03 GeV/c 2
(CM)
A: Watson App.
Sekihara Oset Ramosuncorr. (1405) p
Very Preliminaryassuming uncorrelated Λ*p channel do not interfere with flat dist.
0.0
0.5
1.0
ccoossnnθθ(CM)
2.0 2.2 2.4 2.6 2.8 3.0[GeV/c2]ΛΛp.Minv
3He(K-, Λp)n: Quasi-elastic?
M(
++p
)
M(K
+p+p
)
2.0 2.2 2.4 2.6 2.8 3.0[GeV/c 2]p.Minv
0
50
100
150
200
250 !"!#$%%&%$'(!"!)*+
coun
ts p
er 2
0 M
eV/c
2
nwindow = 0.85 - 1.03 GeV/c 2
(CM)
B: Faddeev App.
Sekihara Oset Ramosuncorr. (1405) p
simple QE?
Very Preliminaryassuming uncorrelated Λ*p channel do not interfere with flat dist.
Structure can be explained with “quasi-elastic K scattering” ? ➡ NO!
3He(K-, Λp)n:
Need deeper strength!
K multiple scattering = “Kpp”
Sekihara Oset Ramos
M(
++p
)
M(K
+p+p
)
2.0 2.2 2.4 2.6 2.8 3.0[GeV/c 2]p.Minv
0
50
100
150
200
250 !"!#$%%&%$'(!"!)*+
coun
ts p
er 2
0 M
eV/c
2
nwindow = 0.85 - 1.03 GeV/c 2
(CM)
A: Kpp+Watson App. Sekihara Oset Ramos
3He(K-, Λp)n: comparison with SOR
0.0
0.5
1.0
ccoossnnθθ(CM)
2.0 2.2 2.4 2.6 2.8 3.0[GeV/c2]ΛΛp.Minv
arXiv:1607.02058v1 [hep-ph] 7 Jul 2016
Very Preliminary
forward n only
QE + “Kpp”K multiple scattering
M(
++p
)
M(K
+p+p
)
2.0 2.2 2.4 2.6 2.8 3.0[GeV/c 2]p.Minv
0
50
100
150
200
250 !"!#$%%&%$'(!"!)*+
coun
ts p
er 2
0 M
eV/c
2
nwindow = 0.85 - 1.03 GeV/c 2
(CM)
B: Kpp+Faddeev App.
Sekihara Oset Ramos
3He(K-, Λp)n: comparison with SOR
0.0
0.5
1.0
ccoossnnθθ(CM)
2.0 2.2 2.4 2.6 2.8 3.0[GeV/c2]ΛΛp.Minv
arXiv:1607.02058v1 [hep-ph] 7 Jul 2016
Very Preliminary
forward n only
QE + “Kpp”K multiple scattering
M(
++p
)
M(K
+p+p
)
2.0 2.2 2.4 2.6 2.8 3.0[GeV/c 2]p.Minv
0
50
100
150
200
250 !"!#$%%&%$'(!"!)*+
coun
ts p
er 2
0 M
eV/c
2
nwindow = 0.85 - 1.03 GeV/c 2
(CM)
A: Kpp+Watson App. B: Kpp+Faddeev App.
Sekihara Oset Ramos
3He(K-, Λp)n: comparison with SOR
0.0
0.5
1.0
ccoossnnθθ(CM)
2.0 2.2 2.4 2.6 2.8 3.0[GeV/c2]ΛΛp.Minv
arXiv:1607.02058v1 [hep-ph] 7 Jul 2016Qualitatively
in good agreement!
calculated without knowing E15 2nd spectrum
forward n only
Very Preliminary
Structure can be explained with quasi-elastic K scattering & Kpp @ -UM?
3He(K-, Λp)n:
Need even deeper strength!
How to understand whole structure?
χ
qualitatively YES! but …
K-+d n+Λ(1405)
37
E31:K-+d n+Λ(1405)
Λ(1405) Σ±π ±
1.51.41.3[GeV/c 2].Minv
E31
yiel
d charge mode average
Very Preliminary
Λ(1405) Σ±π ±
Very Preliminary
K-+d n+Λ(1405)
37
E31:K-+d n+Λ(1405)
Λ(1405) Σ±π ±
1.51.41.3[GeV/c 2].Minv
E31
yiel
d charge mode average
Very Preliminary
Λ(1405) Σ±π ± coun
ts p
er 2
0 M
eV/c
2
0
20
40
60
80
100
120
140!"!#$%%%$&'!"!()* +
(CM)
2.2 2.4 2.6[GeV/c 2]p.Minv
E31
Note: very forward n only
E15
Very Preliminary
K-+d n+Λ(1405)
37
E31:K-+d n+Λ(1405)
Λ(1405) Σ±π ±
1.51.41.3[GeV/c 2].Minv
E31
yiel
d charge mode average
Very Preliminary
Λ(1405) Σ±π ± coun
ts p
er 2
0 M
eV/c
2
0
20
40
60
80
100
120
140!"!#$%%%$&'!"!()* +
(CM)
2.2 2.4 2.6[GeV/c 2]p.Minv
E31
Note: very forward n only
E15
Very Preliminary
larger Fermi-motion?
“Kp” → “Kpp”?
0.0
0.5
1.0
ccoossnnθθ(CM)
2.0 2.2 2.4 2.6 2.8 3.0[GeV/c2]ΛΛp.Minv
M(
++p
)
M(K
+p+p
)
2.0 2.2 2.4 2.6 2.8 3.0[GeV/c 2]p.Minv
0
50
100
150
200
250 !"!#$%%&%$'(!"!)*+
coun
ts p
er 2
0 M
eV/c
2
nwindow = 0.85 - 1.03 GeV/c 2
(CM)
Very Preliminary
How to understand whole structure?
from the shape of deeper region
(sharp drop), the structure in bound
region must be narrow ( 60MeV)~
3He(K-, Λp)n:
0.0
0.5
1.0
ccoossnnθθ(CM)
2.0 2.2 2.4 2.6 2.8 3.0[GeV/c2]ΛΛp.Minv
3He(K-, Λp)n: QE + ?
M(
++p
)
M(K
+p+p
)
2.0 2.2 2.4 2.6 2.8 3.0[GeV/c 2]p.Minv
0
50
100
150
200
250 !"!#$%%&%$'(!"!)*+
coun
ts p
er 2
0 M
eV/c
2
nwindow = 0.85 - 1.03 GeV/c 2
(CM)
B: Faddeev App.
Sekihara Oset Ramosuncorr. (1405) p
simple QE+?
Very PreliminaryIs there No interference?
0.0
0.5
1.0
ccoossnnθθ(CM)
2.0 2.2 2.4 2.6 2.8 3.0[GeV/c2]ΛΛp.Minv
3He(K-, Λp)n: QE + Kpp
if we can neglect interference
rather deep &narrow in width
K-pp?
2.0 2.2 2.4 2.6 2.8 3.0[GeV/c 2]p.Minv
0
50
100
150
200
250 !"!#$%%&%$'(!"!)*+
coun
ts p
er 2
0 M
eV/c
2
nwindow = 0.85 - 1.03 GeV/c 2
(CM)
K elastic?B: Faddeev App.
Sekihara Oset Ramosuncorr. (1405) psimple QE
+Kpp?
K quasi-elastic?
Very Preliminary
3He(K-, Λp)n:
countsper20MeV/c2
2.0 2.2 2.4 2.6 2.8 3.0[GeV/c2]ΛΛp.Minv
0
20
40
60
80
100
120
140
160
180
200
3He(K-, Λp)n:
if we can neglect interference
rather deep &narrow in width
could be OK
0.0
0.5
1.0
ccoossnnθθ(CM)
2.0 2.2 2.4 2.6 2.8 3.0[GeV/c2]ΛΛp.Minv
coun
ts p
er 2
0 M
eV/c
2
2.0 2.2 2.4 2.6 2.8 3.0[GeV/c 2]p.Minv
0
20
40
60
80
100
120
140
160
180
200!"!#$%$'&!"!()* +
(CM)
nwindow = 0.85 - 1.03 GeV/c 2
K-pp?
K elastic?B: Faddeev App.
Sekihara Oset Ramosuncorr. (1405) p
Very Preliminary
K quasi-elastic?
T.Yamaga
◆ Recentresults
43
E-indep.
Reportsstructure /NOstructure
►Experiments►Theoreticalcalc.
KNinteractionmodelE-dep./E-indep.
J-PARC E15 1st
J-PARC E15 2nd??
?
3He(K-, Λp)n:
could be the first convincing data… after a long journey …
with single pole assumption
with double structuresVery Preliminary
E-dep.
Summary
first convincing Kpp signal
finish analysis, including
probably, BK ~ 100 MeV would be excluded
low qK is key for the formation
cf. arXiv:1607.02058 → MΛp = 2354 − 36i MeV B(K) ~ 15 MeVΓ(K) ~ 70 MeV
compact system ?QK ~ 400 MeV/c → ~ 0.5 fm?
44
deeper than -UM ? χ
what needed to be finalize?
examine other possibilities: uncorrelated Σ* p?
full kinematical refit / angular distributions …further theoretical inputs?
what is flat dist. over Dalitz?Λpn
E31?
JP?
THANKS
46
backups
47
15m
E15
J-PARC47
0.6
0.8
1.0
1.2
1.4
1.6
1.8
200
400
600
800
1000
1200
1400
1600
1800 2.0 2.2 2.4 2.6 2.8 3.0
0
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1000
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2500
[GeV/c
2 ]M(Xmiss)
[GeV/c 2]p.Minv48
K- + 3He → ? → Λ + p + n
Y (=K-pp) → Λ + p K- + 3He → Y + n
n-window
nγ m
iss.
(n p
Σ0 )
n miss.
(n p Λ
)
invariant mass of(Λ p) system
mass of missing particle
M(K
+p+p
)
M(Σ
+π+p
)
nπ m
iss.
(n p Λπ
)
M(Λ p)
M(X
mis)K- + 3He → Λ + p + Xmis (Xmis=n)
48
Very Preliminary
49
T.Yamaga
MENU2016@Kyoto
2016.07.2650
2NAprocess
Structure
CMframe
Beam
PRELIMINARYK-+3He:K- +“pp+ns”→Λp+ns
backwardVery Preliminary
kinematically forbidden
qX dependence
twocomponents?
with different qX?
Very Preliminary
51
M(K
+p+p
)
smaller QX?
larger QX?
kinematically forbidden
kinematically forbidden
kinematically forbidden kinematically
forbidden
(40 MeV bin)slice =
0.1 GeV/c
Very Preliminary52
3He(K-, Λp)n T. Hashimoto et al., PTEP (2015) 061D01.B(X) ~ 15 MeVΓ(X) ~ 110 MeVQ(X) ~ 400 MeV/c
E151st
E152ndB(X) ~ 50 ?? MeVΓ(X) ~ 60 ?? MeVQ(X) ~ 400 ?? MeV/c
two structures & Kpp for deeper one!!… very deep
… very compact ( < 0.5 fm ? )
remaining mystery “point like reaction in Λpn final state”
53
Λpn : single-pole?Y. Sada et al., PTEP (2016) 051D01.
n : semi-inclusive
(not hyper deep, though)
… rather narrow
Very Preliminary
❖ Mass :❖ Width :❖ Binding Energy
ΣN cusp + ΣN→ΛN conversion
�⇤p�⌃0p
= 0.92+0.16�0.14(stat)+0.60�0.42(syst)
Prelimin
ary
PTEP 2015, 021D01 Y. Ichikawa et al.
(a) (b) (c)
Fig. 3. Missing-mass square spectra of X obtained in two-proton coincidence events in thed(π+, K + pp)X reaction. Each spectrum shows the mass square of X for a different MMd region: theleft (a) shows the QF" region (MMd < 2.22 GeV/c2), the center (b) shows the “K − pp”-like structureregion (2.22 < MMd < 2.35 GeV/c2), and the right (c) shows the QFY ∗ region (MMd > 2.35 GeV/c2). Thespectra were fitted with three components of #p (dashed line), "0 p (dot-dashed line), and Yπp (dotted line)decay modes.
two-proton coincidence events of the "0 p final state (ii) with the acceptance correction. According tothe simulation, the contribution of the "0 p → "0 p rescattering background is negligible because ofthe two high-momentum proton coincidence. The spectrum was fitted with a relativistic Breit–Wignerfunction:
f (MMd) =(2/π)MMdm0$(q)
(m20 − MM2d)2 + (m0$(q))2. (2)
The mass-dependent width was $(q) = $0(q/q0), in which q (q0) is the momentum of the"0 and proton in the "0 p rest frame at mass MMd (m0). The obtained mass and width are2275 +17−18 (stat.)
+21−30 (syst.) MeV/c
2 and 162 +87−45 (stat.)+66−78 (syst.) MeV, respectively. This cor-
responds to the binding energy of the K − pp system of 95 +18−17 (stat.)+30−21 (syst.) MeV and the
production cross section of the “K − pp”-like structure decaying to "0 p of dσ/d&K − pp→"0 p =3.0 ± 0.3 (stat.) +0.7−1.1 (syst.) µb/sr. The systematic errors of these values were estimated taking intoaccount uncertainties in the fitting ranges, the binning of the missing-mass spectrum, the detec-tion efficiency of two protons in the RCA, and the Breit–Wigner shape by changing the Lorentzianfunction folded with the missing-mass resolution. The differential cross section of the “K − pp”-like structure of the #p decay mode (i) was also estimated from the fitting assuming the samedistribution of MMd . Thus, a branching fraction of the “K − pp”-like structure was obtained as$#p/$"0 p = 0.92 +0.16−0.14 (stat.)
+0.60−0.42 (syst.). This ratio was discussed from a theoretical point of
view and predicted to be 1.2 using the chiral unitary model in Ref. [27].Next, we try to understand the ratio histogram (Fig. 2(c)) with the obtained K − pp mass distribution
of f (M Md). By using the mass distribution for the “K − pp”-like structure and the double-differentialcross section of the inclusive (π+, K +) process d
2σd&d M Md
(M Md)inclusive, we can obtain the ratio
6/8
at Library of Research Reactor Institute, Kyoto U
niversity on February 25, 2015http://ptep.oxfordjournals.org/
Dow
nloaded from
162+87�45(stat.)+66�78(syst.) MeV
2275+17�18(stat.)+21�30(syst.) MeV/c
2Λp/Σ0pK-pp-like structure in Σ0p
Σ0pΛp
T. Nagae
Mthr.(Σπp)
Mthr.(Kpp)
Nothresholdeffectseen?!54
55
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