H.M. QNP Bejing1 1 Hunting -mesic nuclei Hartmut Machner (FZ Jülich & University Duisburg-Essen)...
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Transcript of H.M. QNP Bejing1 1 Hunting -mesic nuclei Hartmut Machner (FZ Jülich & University Duisburg-Essen)...
H.M. QNP Bejing 11
Hunting Hunting -mesic nuclei-mesic nuclei
Hartmut MachnerHartmut Machner(FZ Jülich & University Duisburg-Essen)(FZ Jülich & University Duisburg-Essen)
GEM collaborationGEM collaboration
Outline
• Why are -mesic nuclei interesting?
• Search via production experiments
• Search via Final State Interaction (FSI)
• p+d+3He
• tensor pol. d+d
H.M. QNP Bejing 2
Model for Model for and and ’’ meson in meson in medium (Hirenzaki et al.)medium (Hirenzaki et al.)
Nambu-Jona-Lasinio model with the KMT interaction: explicit breaking of Ua(1) symmetry
Kobayashi, Maskawa Prog.Theor.Phys.44, 1422 (70)Kobayashi, Maskawa Prog.Theor.Phys.44, 1422 (70)G. ’t Hooft, Phys.Rev.D14,3432 (76)G. ’t Hooft, Phys.Rev.D14,3432 (76)
VV(r)(r)
VV’’(r)(r)
VV’’(r)(r)VV(r)(r)
2
VV’’(r)(r)
VV(r)(r)
ggDD : constant : constant ggDD = 0 (w/o KMT term) = 0 (w/o KMT term) ggDD = g = gDD((=0) e=0) e-(-(//0)0) 22
11B
H.M. QNP Bejing 3
Heuristic approachHeuristic approach
• A rather large s-wave -nucleon scattering length lead to the idea of bound -nucleus systems.
• This would be a strong bound system, contrary to pionic atoms (Coulomb bound).
• How to observe?• Recoil free transfer reactions like in hyper-nuclei and in pionic atoms
cases.• Nuclear projectiles:
– d+A3He+[(A-1)]:• Break up protons have same magnetic rigidity as 3He’s. • Large cross section.
– p+A3He+[(A-2)]:• Magnetic rigidity of beam particles differ by a factor of two from 3He’s. • Small cross section.
H.M. QNP Bejing 4
Order of magnitudeOrder of magnitude
HHG
d,3He
L.-C. Liu
H.M. QNP Bejing 5
Missing mass spectroscopyMissing mass spectroscopy
emitted particleemitted particle
Incident particleIncident particle
targettargetmesonmeson
deuteron-holedeuteron-hole
Momentum transfers for Momentum transfers for -mesic nuclei-mesic nuclei formation formation
A A-3
p
3He
p
p-
N *
N *
N *
N *
0
20
40
60
80
100
120
140
160
180
200
q-
mes
ic (
Me V
/ c)
1600 1700 1800 1900p
beam (MeV/c)
B=0 MeV
B=-10 MeV
B=-20 MeV
p+27Al3He+(25Mg)
B=-30 MeV
B=-70 MeV
H.M. QNP Bejing 6
Previous searchesPrevious searches
Pfeiffer et al. PRL: +3Hep0+p+X, 3.5
Sokol et al.: +12Cp++n+X; Both ejectiles are anti-correlated;
<Ep>=300 MeV, <En>=100 MeV
Lieb et al. (p+,p)
Chrien et al. PRL• q=200 MeV/c• inclusive
H.M. QNP Bejing 7
27 3 25
0*
( can not decay, becau
(1535
se its bound!)
)
p Al He Mg
n N n
p
p
-
ReactionsReactions
3He in BIG KARL, all beam momentum
p-p back to back in ENSTAR
3-fold coincidence + 3 more constraints!
H.M. QNP Bejing 8
ENSTAR
3
2 2
dp H
Ae
A
- -
0*
0(1535)
p
nN N
p
n
pp
pp
-
Detector
TOF
H.M. QNP Bejing 9
ENSTAR DetectorENSTAR Detector
NIM A 596 (08) 31
H.M. QNP Bejing 10
Mounting phaseMounting phase
H.M. QNP Bejing 11
Proton + Aluminium target
Particle identification with BK focal plane detectors
(high threshold cuts light particles)
Event of interest:Two correlated particles: 5+2/3=7/8 fold coincidencePion leaves the detector: outer layer firesProton stopped in the middle layer
H.M. QNP Bejing 12
Two spectrometer settings
H.M. QNP Bejing 13
Time- andTime- and 3 3He spectraHe spectra
100
101
102
103
104
105
cou n
ts /
4 M
eV
-30 -20 -10 0BE (MeV)
23.79 23.80 23.81 23.82MM (GeV)
3He in BK+ENSTAR+bb
3He in BK+ENSTAR
only 3He in BK
0
10
20
30
0
200
400
600
800
cou
nts
0
10000
20000
30000
40000
50000
0 200 400 600 800 1000time (arb. units)
FP ENSTAR
FP (3He) ENSTAR
FP (3He) ENSTARall gates
H.M. QNP Bejing 14
η-nucleus formation cross section estimation
L ≈ 5*1035 cm-2 ≈75 hours of the beam for each setting
≈ 5 * 108 particles per second on the target1 mm Aluminium target
efficiency: 0.70±0.07 loss due to geometry and cuts: Bump = 50 pb
εbranch = 1/3
L
N
exp. 152 54(stat.) 21(syst.) pb N* p N (2Tz+1)
N0* p- p 2
N0* p0 n 1
N+* p+ n 2
N+* p0 p 1
H.M. QNP Bejing 15
Summed dataSummed data
PRC 70 (2009) 012201(R)
H.M. QNP Bejing 16
2 2 2 2iB B
f
p df f FSI f FSI
p d
20
11
12f f
FSIi a p a r p
-
classical description in „a“ and „r0“
alternative description
- final state interaction
Tacid assumption:
s-wave, and then d/d=/4p
Sign convention: Goldberger
H.M. QNP Bejing 17
Binding conditionsBinding conditions
Quasi-bound requires:
• Im(aA) > 0 from unitarity
• |Im(aA)| < |Re(aA)| to have a pole in the negative energy half plane
•Re(aA) < 0 to have a bound state, but
|FSI|2 Re(aA)2
|Q0(3He)|<|Q0(4He)|
Otherwise: virtual (unphysical) state
H.M. QNP Bejing 18
Total cross sections
100
200
300
400
500
600
700
800
(n
b)
0
100
200
300
400
500
0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2 1.3 1.4 1.5 = p/m
-2 0 2 4 6 8 10 12 (MeV)
BilgerAdamRausmannMersmannSmyrskiMeyerBanaigsLoireleuxKirchnerGEM *0.73
FSI (Sibirtsev)
pd3He
H.M. QNP Bejing 19
3He- production amplitude
T. Mersmann et al., PRL 98 (07) 242301
3
0.1 1.00.5 0.910.7 0.8 1.5 2.6 fm
Hea i
- -
0.20 0.01.9 0.1 2.1 0.2 fmr i
-
COSY11 + old data <50 MeV/c
no need for effective range
PLB 649 (07)258
3 2.9 2.7 3.2 1.8 fmHe
a i 0| | 0.30 MeVQ
H.M. QNP Bejing 20
dd
Eur. Phys. J. A 26 (2005) 421
H.M. QNP Bejing 21
GEM ddGEM dd
beam direction
point
target
Luminosity Right Scintillators
Luminosity Left Scintillators
M detector
In order to extract s-wave production, tensor polarised deuteron beam
Target area:
M detector
beam directiontarget
point
H.M. QNP Bejing 22
Raw dataRaw data
(p+1)/2
(p-1)/2
-(p+1)/2
-(p-1)/2
H.M. QNP Bejing 23
Unpolarised cross sectionsUnpolarised cross sections
Exp. a0 a2 a4
ANKE1.30
±0.18
-0.79
±0.19
GEM1.27
±0.03
-0.29
±0.06
1.65
±0.07
s, p and d-waves!
H.M. QNP Bejing 24
Excitation FunctionExcitation Function
Same momentum range as in p+d, but less data points. Cross section less than 5%!
How to extract s-wave?
H.M. QNP Bejing 25
Polarised beamPolarised beam
dp elastic scattering
(radians)0 1 2 3 4 5 6
un
po
l/N
po
lN
0.97
0.98
0.99
1
1.01
1.02
1.03
1.04
1.05
= +1)zz
] (p+0.019cos21.00[1+0.0011+0.0354cos= -1)
zz] (p-0.016cos21.02[1-0.0007+0.0352cos
H.M. QNP Bejing 26
H.M. QNP Bejing 27
Better fit than partial wave amplitudes (s, p, 2d waves), because less parameters (4 instead of 7)
Angular dependence due to s-d interference
H.M. QNP Bejing 28H. M., Mumbai, Febr. 09 28
FinalFinalresultresult
NP A 821 (2009) 193
PWA
spin ampl.
H.M. QNP Bejing 29
Final resultFinal result
scatt. length
effective range
30 0| | 4MeV > | ( He) |Q Q
H.M. QNP Bejing 30
Summary Search for -mesic nuclei employing recoil free kinematics. We see an enhancement in the spectra after detecting 3 final
particles: 3He at zero degree and p-+p back to back.
25Mgbound state: BE13 MeV, FWHM10 MeV 5 effect We have measured angular distributions of cross sections and
tensor analysing power for the reaction dd at 16.6 MeV above threshold
s-wave strength could be extracted s-wave strength of other experiments (Willis et al., Wronska et
al.) extracted FSI shows Im a (-) = 0.0(5) fm. This indicates a small
absorption because the nucleons are strongly bound The -nucleus levels in heavy nuclei thus might be fairly
narrow.
H.M. QNP Bejing 31
The GEM CollaborationThe GEM CollaborationM. Abdel-Barya, S. Abdel-Samad a, A. Budzanowski d, A. Chatterjee i, J. Ernst g, P. Hawranek a,c, R.
Jahne, V. Jhai, S. Kailasi, K. Kilian a, Da. Kirilova,h, Di. Kirilovh, S. Kliczewski d, D. Kolev f,M. Kravcikova m, T. Kutsarova e, M. Lesiaka,c, J. Lieb j, H. Machner a, A. Magiera c, G. Martinska l,
H. Nann k, N. Piskinovh, L. Pentchev e, D. Protic a, J. Ritman a, P. von Rossen a, B. J. Roy i, P. Shuklai,R. Siudak d, I. Sitnikh, M. Ulicny a,l, R. Tsenov f, J. Urban l, G. Vankovaa,f, C. Wilkinn, G. Wüstnerb
a. Institut für Kernphysik, Forschungszentrum Jülich, Jülich, Germany b. Zentrallabor für Elektronik, Forschungszentrum Jülich, Jülich, Germany
c. Institute of Physics, Jagellonian University, Krakow, Poland d. Institute of Nuclear Physics, Pan, Krakow, Poland
e. Institute of Nuclear Physics and Nuclear Energy, Sofia, Bulgaria f. Physics Faculty, University of Sofia, Sofia, Bulgaria
g. Institut für Strahlen- und Kernphysik der Universität Bonn, Bonn, Germany h. LHE, JINR, Dubna, Russia
i. Nuclear Physics Division, BARC, Bombay, India j. Physics Department, George Mason University, Fairfax, Virginia, USA
k. IUCF, Indiana University, Bloomington, Indiana, USA l. P. J. Safarik University, Kosice, Slovakia
m. Technical University, Kosice, Kosice, Slovakia n. Department of Physics & Astronomy, UCL, London, U.K.
H.M. QNP Bejing 32
Thank you for your attention
H.M. QNP Bejing 33
FSIFSI
H.M. QNP Bejing 34
Excitation function:dp→3He
2/nfree=0.82