The results of the study of dp-elastic scattering at the energies from 500 to 1000 MeV/nucleon

1. The results of the study of dp-elastic scattering at the energies from 500 to 1000 MeV/nucleon A.A Terekhin et al. Joint Institute for Nuclear Research, Dubna, Russia HS’2015

2. Introduction The purpose of DSS (Deuteron spin structure) project is the broadening of the energy and angular ranges of measurement of different observables in processes including 3-nucleon systems. The study of the dp-elastic scattering at various energies in large angle range is one of directions in this domain. The experimental setup at internal target station (ITS) at Nuclotron allows us to obtain the different observables at angle range 60-140o in the c.m.s. We shown in this presentation preliminary data of differential cross section for dp-elastic scattering at 500, 650,700,750,900 and 1000 Mev/n, obtained at ITS Nuclotron.

4. Measurements on the Internal target station

5. Layout of the counters with respect to the beam direction 500-900 MeV/n 1000 MeV/n P = 20x60x20 mm3 D = 10x40x24 mm3 PP = 50x50x20 mm3 P = 20x60x20 mm3 D = 50x50x20 mm3 PP =f100х200 mm3

6. VME Data Acquisition System The VME based data acquisition system was used for the data taking from scintillation detectors. TQDC-16 – 16 - channel time and charge digitizer TQDC-16 GUI Controls TTCM

7. TheestimationofthebackgroundintheamplitudedatawasperformedbyusingtheTheestimationofthebackgroundintheamplitudedatawasperformedbyusingthe temporarygatesonthedeuteronandprotontimedifferencespectra.Thesubtraction ofthetimingsignalfromdeuteron-andproton-counterswas madebyusingthecutfor signalamplitudescorrelationInthisdistribution the dp-elasticscatteringevents(Idomain)andthebackground(IIandIIIdomains)areselectedsothatthewidthof bothdomainsareequal. A - Theamplitudedistributionforprotoncounterbyusingthese timing gates. B - Thesubtractionoftheresultingspectraallowsreducingofthebackground

8. CH2-C subtraction The next stage is the CH2-C subtraction procedure. Carbon background subtraction deduced from the normalization in the interval amin<a<amax, were a - channels of CH2- and C-amplitude distributions. I.e. were k - normalization coefficient, NCH2 and NC - CH2- and C-amplitude distributions integrals in a-interval. The carbon background can be subtracted as:

9. Differential cross section at 1000 MeV/n The data for differential cross section are compared with the world data and with the theoretical predictions. The new data are shown by the solid squares [arXiv:1503.07968].The errors are the statistical only. The systematic errors are shown by the solid gray band. The data obtained earlier for forward angles are shown by the solid circles. The open triangles are world data obtained with a monochromatic protons beam at the Brookhaven Cosmotron by using a liquid-deuterium target. Squares – new data Circles – the data obtained early for forward angles [Terekhin A.A. et al. EPJ A48, 2012. P.182.] Triangles - Bennett G. W. et al. Phys. Rev. Lett. 1976. V.19 P. 387-390. The dashed and solid lines are the calculations without and with DS term, respectively. [Ladygina N.B. et al. EPJ A42, 2009. P.91.] The dashed and solid lines are the calculations without and with DS term, respectively. One can see that the new data at Qc.m.< 90o are in good agreement with the world data. The discrepancy is increased at large angles, nevertheless, the data are in agreement with the errors which increase with the angle increasing. On the other hand, there is better agreement with theoretical calculations taking into account DS at these angles. This figure shows that the single scattering mechanism does not reproduce the experimental data at the scattering angles Qc.m larger than 45o. The inclusion of the double scattering term in the calculations provides better agreement with the experimental results.

10. Differential cross section 650 MeV/n 750 MeV/n Triangles – data at 641.3 MeV/n (Culmez E. Phys.Rev.C, V43, №5, 1991) Blue triangles – data at 792.7 MeV/n (Culmez E. Phys.Rev.C, V43, №5, 1991) Green triangles – data from 800 MeV/n (Winkelmann E. Phys.Rev.C, V21, №6, 1980)

11. The detectors misalignment determination The determination of the detectors misalignment were performed to improve the accuracy of the experiment. The following measurements were performed at the 700 MeV/n for each angle scattering in the c.m.s. Since the angle span of the deuteron counter in the c.m.s. is wider than the angle span of the proton counter the deuteron counter is fixed at kinematical angle in the lab. sys. but the proton counter is moved around corresponded angle. For this case the relative yields was measured. The experimental relative yields for proton detectors as a function of detector angle for 70o in the c.m.s. The angle span of the deuteron- and proton - counter The dp-elastic scatterind events simulation We performed the simulation of dp-elastic scatterind events by using the Pluto peckage. The statistics is reduced about two timesif the shift of the detectoregual 2o in the c.m.s. After this the measurements to obtained of the dp-elastic scatterind yields were performed. The yield is normalized by guasi-elastic scattering yield. Filled and open symbols correspond to yields for one and other proton detectors.

12. Differential cross section 700 MeV/n The angular dependence for differential cross section at 700 MeV/n The data for 500 and 900 MeV/n are in the at the analysis stage

13. Conclusion The procedure on the dp-elastic scattering differential cross section at high energies at ITS at Nuclotron using CH2 - C subtraction is established. The data obtained at 1000 MeV/n are compared with the calculations performed within the framework of the relativistic multiple scattering theory. It is shown that taking into account the double scattering term improves the description of the obtained experimental results. The preliminary differential cross section data for dp-elastic scattering at 500,650,750 and 900 MeV/n are obtained. New results are compared with the existing data for similar values of energies.

14. Thank you for attention!