Differential cross section in deuteron-proton elastic
scattering at 1.25 GeV/u
P.Kurilkin, A.Kurilkin, V.Ladygin, T.Vasiliev
LHEP-JINR
For the HADES collaboration
October 3-7, 2011 in Rez/Prague, Czech Republic
Outline
Introduction
Data analysis
• dp- elastic events selection
• dp- elastic scattering simulation at 1.25 GeV/u
• Efficiency and acceptance correction
• Preliminary results
Conclusion
2
dp elastic scattering at the energy 270 MeV
NN Forces only
NN interaction: CD-Bonn, AV18,
Nijmegen I,II & 93
NN + TM’(99) 3NF
NN interaction: CD-Bonn, AV18,
Nijmegen I,II
NN + Urbana IX 3NF
NN interaction: AV18
Relativictic calc. (AV18)
Nonelativictic calc. (AV18)
N.Sakamoto et al., Phys. Lett. B 367, 60 (1996)
H. Sakai et al., Phys. Rev. Lett. 84, 5288 (2000)
K. Sekiguchi et al., Phys. Rev. C65, 034003 (2002)
K. Ermish et al., Phys. Rev. C 68, 51001 (2003)
K. Sekiguchi et al., Phys. Rev. Lett. 95, 162301 (2005)
3
nd and pd elastic scattering measurements
at the energy of 250 MeV
Calculations even including
3NF underestimate the data at
Θc.m ~110-180 deg
Relativistic calculations
improve the fit of the data
only at Θc.m >160 deg
H.Sakai, FB18, Santos, Brazil, (2006)
Y. Maeda et al., Phys. Rev. C 76, 014004 (2007)
K. Hatanaka et al., Phys. Rev. C 66, 044002 (2002)
34
World data:
N.E.Booth et al., Phys.Rev.D4 (1971) 1261
J.C.Alder et al., Phys.Rev.C6 (1972) 2010
Relativistic multiple scattering model calculation:
N.B.Ladygina, Eur.Phys.J, A42 (2009) 91
Red circles are the preliminary LHEP-JINR results:
DSS-project at Nuclotron.
5
HADES experiment at SIS18, GSI
Spectrometer with …
High geometrical acceptance
Full azimuth, polar angles 18˚ - 85˚
Pair acceptance  0.35
High invariant mass resolution (2.5% at /
pole mass)
Low-mass tracking (superconducting toroidial
magnet & multi-wire drift chamber (MDC),
single cell resolution 100 mm)
FW
Powerful PID capabilities: d/p/K/p/e
RICH, TOF/TOFino, Pre-Shower,
FW hodoscope: added 2007
High background rejection & rate capability,
dedicated LVL2 trigger:
LVL1: charge particle multiplicity
LVL2: single electron trigger
Schematic view of the HADES
spectrometer
4
6
dp elastic events selection at 1.25 GeV/u.
The dp- elastic events candidate selection:
0.22 < tanθ0 * tanθ1< 0.4, ||φ0- φ1|-180| < 5°
The angle-momentum distribution for
dp- elastic scattering candidates compared
with kinematical predictions.
7
Momentum and angular resolution for deuterons
Uniform single tracks distribution (p, cosθ,φ) in the laboratory frame.
8
Momentum and angular resolution for protons
Uniform single tracks distribution (p, cosθ,φ) in the laboratory frame.
9
Graphical cuts for the dp- elastic event selection at 1.25 GeV/u
The angular-momentum distribution for dp- elastic scattering
candidate. Blue and red contours are the graphical criteria to the
deuteron and proton selection.
10
Simulation of dp- elastic scattering at 1.25 GeV/u
The pd- elastic cross section data versus
scattering angle in c.m.s. at 1GeV.
G.W. Bennet et al., Phys. Rev. Lett. 19, 387 (1967)
The angular distribution used for
simulation of dp- elastic scattering at
1.25 GeV/u. The cross section data was
fixed at the cosθ* > 0.886.
11
Simulation of dp elastic scattering at 1.25 GeV/u
Correlation between difference of
180-|Δφdp| and tanθd * tanθp
The distribution of the tanθd * tanθp for
dp- elastic scattering at 1.25GeV/u
12
Selection of the particles in the region where graphical
cuts of deuteron and proton overlap.
Real data
Simulated data
The experimental time difference distribution between two tracks.
13
Quality of the dp elastic events selection
The distribution of the 180º - (θd*+θp*) for the angular region 73º ± 3º (Left panel)
and for the 105º ± 3º (Right panel) in the c.m.s.
8
14
The simulation results of the dp elastic scattering at 1.25 GeV/u
GeantInput
Accepted
18°< θlab<85°
Reconstructed
18°< θlab<85°
18°< θlab<85°
Distribution of the dp- elastic scattering yield as a
function of the cosθ*. Black, blue and red histograms are
the distribution for dp-elastic scattering using as the
geant input, accepted and reconstructed, respectivelly.
Acceptance and efficiency reconstruction
coefficients for the dp- elastic scattering
events.
15
Efficiency and acceptance correction for dp elastic scattering
at 1.25 GeV/u
d

N
dp 
pp 
dp

*
*
*
d

N

pp




2



(cos

)
exp
dN

4
*
32
*
dN
dp
dp
exp
dN dp
is efficiency and
acceptance corrected
•
•
•
•
•
rkMult ≥ 2
|Δφdp| < 5º
0.17< tanΘ*d*tanΘ*p < 0.4
18º < Θlab [d,p] < 85º

(
3
.
85

0
.
25
)

10
mb
eve
pp

9
N
pp
http://hades-wiki.gsi.de/pub/SimAna/
NormalizationForPpAndDp/pp_elastic260109.pdf
16
Differential cross section of dp elastic scattering at GeV/u region
HADES results
Experimental data:
E. Winkelman et al., Phys. Rev. C 21, 2535 (1980)
G.W. Bennet et al., Phys. Rev. Lett. 19, 387 (1967)
E.Coleman et al., Phys. Rev. Lett. 16, 741 (1966)
N.E. Both et al., Phys. Rev. D 4, 1261 (1971)
E. Gulmez et al., Phys. Rev. C 5, 2067 (1991)
17
Differential cross section data for dp elastic scattering at fixed
scattering angle in the cm.
s-16
s-16
Experimental data:
Constituent counting rules:
E. Winkelman et al., Phys. Rev. C 21, 2535 (1980)
G.W. Bennet et al., Phys. Rev. Lett. 19, 387 (1967)
E.Coleman et al., Phys. Rev. Lett. 16, 741 (1966)
N.E. Both et al., Phys. Rev. D 4, 1261 (1971)
E. Gulmez et al., Phys. Rev. C 5, 2067 (1991)
V.A. Matveev, R.M. Muradyan and A.N. Tavkhelidze,
Lett. Nuovo Cimento 7, 719 (1973)
Yu.N.Uzikov, JEPT, Lett., 81, 303 (2005)
18
Summary
• The preliminary results on differential cross section for dpelastic scattering at the energy of 1.25 GeV/u are obtained.
• The HADES data on dp- elastic scattering at are in the
reasonable agreement with the world data.
Outlook:
• Data analysis with hydra 8.21.
• Obtain the final results on the differential cross section in dp
elastic scattering at Td=2. 5 GeV.
• Estimation of the systematic errors of the differential cross
section measurement.
19
Many thanks to
A.Rustamov, K.Lapidus, T.Galatyuk, G.Agakishiev,
V.Pechenov, O.Pechenova, M.Lorenz and other
people who helped us in our analysis!!!
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Thank you for your attention!!!
21
Short internucleonic distances



When the distances between the nucleons are comparable with
the size of the nucleon, the nucleon-nucleon interaction is nonlocal.
Fundamental degrees of freedom in the frame of QCD are the
quarks and gluons. These degrees begin to play a role at the
internucleonic distances comparable with the size of the nucleon.
(∆∆, N*N, N*N*, 6q components in the deuteron)
At high energy s and large transverse momenta pt the
constituent counting rules are working. For the binary
reactions:
d

f(
t/s
)
(
AB

CD
)
n
2
dt
s
n

N

N

N

N
A
B
C
D
(Matveev, Muradian, Tavkhelidzhe, Brodsky, Farrar et al. )
22
Quark degrees of freedom
Yu. N. Uzikov
(JEPT Lett, 81, pp. 303-306, 2005)
For the reaction dd → 3Hen
N

N

N

N

2

22
A
B
C
D
For the reaction dp → dp
N

N

N

N

2

16
A
B
C
D
The regime corresponds to CCR
occurs already at Td ~ 500
The investigation of the energy dependence ofMeV
the cross section in dp elastic
scattering is very desirable to obtain the information on the deuteron internal
structure.
23