Breakup reaction for polarimetry of tensor polarized deuteron beams 1 A.P. Kobushkin Bogolyubov Institute for Theoretical Physics Metrologicheskaya str. 14B Kiev, Ukraine E.A. Strokovsky Laboratory of High Energy Physics Joint Institute for Nuclear Research , Dubna, Russia E.A.Strokovsky, Dubna, Based on talk given at the “SYMMETRIES AND SPIN (SPIN-Praha-2012)” Conference, Prague, July 1 - 8, 2012; JINR preprint Е , Dubna, JINR, See also A.P.K. and E.A.S., Phys. Rev. C 87 (2013),

2 Common interest to the lightest nuclei structure at short distances or high relative momenta between constituents resulted in lack of attention to behaviour of spin-dependent observables at long distances or at small relative momenta. To avoid this bias we paid special attention to behaviour of the observables at this small relative momenta region as well. E.A.Strokovsky, Dubna, The goal of this talk is to demonstrate that: Deuteron breakup at 0 o can be used for local polarimeters at SPD as well as MPD. Polarization monitoring can be easily realized. Existing data obtained with polarized deuterons contain more physical information than it was extracted so far.

3 Selected experimental data concerning the deuteron structure (hadron probes; reminder). E.A.Strokovsky, Dubna,

4 Total cross section for deuteron-proton scattering (intermediate energy region) E.A.Strokovsky, Dubna,

Polarization transfer coefficient (from vector polarized deuteron to proton) Light cone variable 5 Breakup (d,p)X at 0 o, backward elastic scattering Cross section The key tool: polarized deuteron beams in Dubna and Saclay. Tensor analysing power E.A.Strokovsky, Dubna,

6 Deuteron breakup and the D 2 parameter for deuteron E.A.Strokovsky, Dubna,

7 At small k: Definition for deuteron in literature:

8 M – nucleon mass, B – binding energy of deuteron k in Fm -1 k in GeV/c Knutson&Haeberli (1976): D 2 = (0.432  0.032); W. Gruebler et al (1980):  d = (  ); = -(22.19  0.82) when k is taken in GeV/c (Instead of  d many people often use notation  d ). E.A.Strokovsky, Dubna, D d 2 is positive.

9 Reminder: existing data on deuteron breakup (inclusive) E.A.Strokovsky, Dubna,

10 Zoom at the next slide E.A.Strokovsky, Dubna,

11 Excluded from the fit Deuteron breakup by protons (Z=1) Energy range: T kin =2.1 GeV (Saclay, data tables publ. in 1987 & 1989), 7.4 GeV (Dubna, data tables publ. in 1996) E.A.Strokovsky, Dubna,

12 Knutson&Haeberli (1976): 2D 2 = (22.19  0.82) (k in GeV/c) W. Gruebler et al : (1980 ): 2D 2 = (24.80  0.67) Our fit of the p(d,p)X data: 2D 2 = (23.70  0.33) Theoretical value of  d (or  d ) is around  ; experimental value (averaged) is (4); what results in 2D 2 =  0.38 Taking into account that: the used spectator model does not include some possible corrections (Coulomb first of all) and only statistical errors are taken into account and those were not a dedicated measurements of T 20 at low q (the main interest was to the high q region), the obtained value is in rather good agreement with existing data even without optimization of the q-range. The p(d,p)X reaction in GeV region can be used as additional source for data on  d (or  d ). E.A.Strokovsky, Dubna,

13 From V.M.Krasnopol’sky et al, PhL 165B (1985) p.7: Potential: RSC  d =  2D 2 = 25,09 RHC  d =  2D 2 = 24,80 Yale  d =  2D 2 = 24,32 Paris  d =  2D 2 = 24,99 MSU (old)  d =  2D 2 = 25,76 From E. Epelbaum, Braz. Journ. Ph., v. 35, p (2005): N 3 LO in chiral EFT:  d =  2D 2 = 24,32  d =  2D 2 = 24,42 From NN potential by Nijmegen group: Nijm II:  d =  2D 2 = 24,14 Nijm 93:  d =  2D 2 = 24,17 Reid93:  d =  2D 2 = 24,07 Our fit of the p(d,p)X (0 o ) data: 2D 2 = (23.70  0.33) E.A.Strokovsky, Dubna,

14 Effects of the Coulomb interaction (hints) E.A.Strokovsky, Dubna,

15 A.P. KOBUSHKIN, YA.D. KRIVENKO-EMETOV, Ukr. J. Phys V. 53, N 8, p.751 Dash-dotted line: quasi-impulse approx. Dashed line: multiple scatt. + Pauli principle for all constutuent quarks in deuteron; Full line: Coulomb interaction is added Deuteron breakup by carbon (Z=6) E.A.Strokovsky, Dubna,

16 Deuteron breakup by carbon (Z=6) T kin = 7.4 GeV (Dubna, data tables publ. in 1990 & 1996) E.A.Strokovsky, Dubna,

17 (1) deuteron beam polarimetry at intermediate and high energies both for tensor polarization (energy independent, high figure of merit  T 20 2  !) and vector polarization (proton polarization must be measured); (2) obtaining new experimental data about the deuteron asymptotic D/S ratio; (3)experimental estimates of Coulomb effects in deuteron breakup; the Coulomb effects in T 20 are (apparently) small. Conclusions. Deuteron breakup with spectator proton detection at 0 o at momentum in vicinity of p d /2 is very useful reaction for: E.A.Strokovsky, Dubna,

18 Thank you! E.A.Strokovsky, Dubna,