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

2 Outline Introduction Data analysis dp- elastic events selection dp- elastic scattering simulation at 1.25 GeV/u Efficiency and acceptance correction Preliminary results Conclusion

3 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, (2002) K. Ermish et al., Phys. Rev. C 68, (2003) K. Sekiguchi et al., Phys. Rev. Lett. 95, (2005) 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)

nd and pd elastic scattering measurements at the energy of 250 MeV Calculations even including 3NF underestimate the data at Θ c.m ~ deg K. Hatanaka et al., Phys. Rev. C 66, (2002) Y. Maeda et al., Phys. Rev. C 76, (2007) Relativistic calculations improve the fit of the data only at Θ c.m >160 deg H.Sakai, FB18, Santos, Brazil, (2006) 3 4

World data: N.E.Booth et al., Phys.Rev.D4 (1971) 1261 J.C.Alder et al., Phys.Rev.C6 (1972) 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 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) 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 4 6

7 dp elastic events selection at 1.25 GeV/u. The dp- elastic events candidate selection: 0.22 < tanθ 0 * tanθ 1 < 0.4, ||φ 0 - φ 1 |-180| < 5° The angle-momentum distribution for dp- elastic scattering candidates compared with kinematical predictions.

Momentum and angular resolution for deuterons 8 Uniform single tracks distribution (p, cosθ,φ) in the laboratory frame.

Momentum and angular resolution for protons 9 Uniform single tracks distribution (p, cosθ,φ) in the laboratory frame.

Graphical cuts for the dp- elastic event selection at 1.25 GeV/u 10 The angular-momentum distribution for dp- elastic scattering candidate. Blue and red contours are the graphical criteria to the deuteron and proton selection.

11 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* > 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 tanθ d * tanθ p for dp- elastic scattering at 1.25GeV/u Correlation between difference of 180-|Δφ dp | and tanθ d * tanθ p 12

Selection of the particles in the region where graphical cuts of deuteron and proton overlap. The experimental time difference distribution between two tracks. Simulated data Real data 13

Quality of the dp elastic events selection The distribution of the 180 º - (θ d * +θ p * ) for the angular region 73º ± 3º (Left panel) and for the 105º ± 3º (Right panel) in the c.m.s. 8 14

15 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°< θ lab <85 ° Acceptance and efficiency reconstruction coefficients for the dp- elastic scattering events.

16 Efficiency and acceptance correction for dp elastic scattering at 1.25 GeV/u rkMult ≥ 2 |Δφ dp | < 5º 0.17< tanΘ * d *tanΘ * p < º < Θ lab [d,p] < 85º is efficiency and acceptance corrected NormalizationForPpAndDp/pp_elastic pdf

17 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

18 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

19 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 Obtain the final results on the differential cross section in dp elastic scattering at T d =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!!! 20

Thank you for your attention!!! 21

22 Short internucleonic distances  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 p t the constituent counting rules are working. For the binary reactions : (Matveev, Muradian, Tavkhelidzhe, Brodsky, Farrar et al. )

23 Quark degrees of freedom Yu. N. Uzikov (JEPT Lett, 81, pp , 2005) For the reaction dd → 3 Hen For the reaction dp → dp The regime corresponds to CCR occurs already at T d ~ 500 MeV 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.