Differential cross section in deuteron-proton elastic scattering at 1.25 GeV/u

P.Kurilkin, A.Kurilkin, V.Ladygin, T.Vasiliev

LHEP-JINRFor the HADES collaboration

October 3-7, 2011 in Rez/Prague, Czech Republic

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Outline

IntroductionData analysis• dp- elastic events selection• dp- elastic scattering simulation at 1.25 GeV/u• Efficiency and acceptance correction• Preliminary resultsConclusion

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dp elastic scattering at the energy 270 MeV

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)

NN Forces onlyNN 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)

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

K. Hatanaka et al., Phys. Rev. C 66, 044002 (2002)

Y. Maeda et al., Phys. Rev. C 76, 014004 (2007)

Relativistic calculations improve the fit of the data only at Θc.m >160 deg H.Sakai, FB18, Santos, Brazil, (2006)

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World data:N.E.Booth et al., Phys.Rev.D4 (1971) 1261

J.C.Alder et al., Phys.Rev.C6 (1972) 2010

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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.

HADES experiment at SIS18, GSI

Schematic view of the HADES spectrometer

FW

Spectrometer with …

High geometrical acceptanceFull 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)

Powerful PID capabilities: d/p/K/p/eRICH, TOF/TOFino, Pre-Shower,FW hodoscope: added 2007

High background rejection & rate capability, dedicated LVL2 trigger:LVL1: charge particle multiplicityLVL2: single electron trigger

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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.

Momentum and angular resolution for deuterons

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Uniform single tracks distribution (p, cosθ,φ) in the laboratory frame.

Momentum and angular resolution for protons

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Uniform single tracks distribution (p, cosθ,φ) in the laboratory frame.

Graphical cuts for the dp- elastic event selection at 1.25 GeV/u

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The angular-momentum distribution for dp- elastic scattering candidate. Blue and red contours are the graphical criteria to the deuteron and proton selection.

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Simulation of dp- elastic scattering at 1.25 GeV/u

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.

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)

Simulation of dp elastic scattering at 1.25 GeV/u

The distribution of the tanθd * tanθp for dp- elastic scattering at 1.25GeV/u

Correlation between difference of 180-|Δφdp| and tanθd * tanθp

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Selection of the particles in the region where graphical cuts of deuteron and proton overlap.

The experimental time difference distribution between two tracks.

Simulated dataReal data

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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.

814

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The simulation results of the dp elastic scattering at 1.25 GeV/u

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.

GeantInput

Accepted

Reconstructed

18°< θlab<85°

18°< θlab<85°

18°< θlab<85°

Acceptance and efficiency reconstruction coefficients for the dp- elastic scattering events.

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Efficiency and acceptance correction for dp elastic scattering at 1.25 GeV/u

• rkMult ≥ 2• |Δφdp| < 5º• 0.17< tanΘ*

d*tanΘ*p < 0.4

• 18º < Θlab [d,p] < 85º

•

***

dp

pp

ppdp N

Nd

d

exp*32*4dp

dNdp

dN

is efficiency and acceptance corrected

expdpdN

)(cos2

eventsmbN pp

pp 910)25.085.3(

http://hades-wiki.gsi.de/pub/SimAna/ NormalizationForPpAndDp/pp_elastic260109.pdf

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Differential cross section of dp elastic scattering at GeV/u region

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)

preliminary

N.E. Both et al., Phys. Rev. D 4, 1261 (1971)E. Gulmez et al., Phys. Rev. C 5, 2067 (1991)

HADES results

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Differential cross section data for dp elastic scattering at fixed scattering angle in the cm.

Constituent counting rules:

V.A. Matveev, R.M. Muradyan and A.N. Tavkhelidze, Lett. Nuovo Cimento 7, 719 (1973)Yu.N.Uzikov, JEPT, Lett., 81, 303 (2005)

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)

s-16 s-16

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Summary

• The preliminary results on differential cross section for dp- elastic 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.

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!!!

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Short internucleonic distances

2

)/()(

ns

stfCDAB

dt

d

When the distances between the nucleons are comparable with the size of the nucleon, the nucleon-nucleon interaction is non-local.

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:

(Matveev, Muradian, Tavkhelidzhe, Brodsky, Farrar et al. )

DCBA NNNNn

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Quark degrees of freedom

Yu. N. Uzikov

(JEPT Lett, 81, pp. 303-306, 2005)

For the reaction dd → 3Hen

For the reaction dp → dp

The regime corresponds to CCR occurs already at Td ~ 500 MeV

222 DCBA NNNN

162 DCBA NNNN

The investigation of the energy dependence of the cross section in dp elastic scattering is very desirable to obtain the information on the deuteron internal structure.