Breakup reaction for polarimetry of t ensor polarized deuteron beams

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Breakup reaction for polarimetry of tensor polarized deuteron beams

A.P. KobushkinBogolyubov Institute for Theoretical Physics

Metrologicheskaya str. 14B03680 Kiev, UkraineE.A. Strokovsky

Laboratory of High Energy PhysicsJoint Institute for Nuclear Research

141980, Dubna, Russia

E.A.Strokovsky, Dubna, 18.03.2013

Based on talk given at the “SYMMETRIES AND SPIN (SPIN-Praha-2012)” Conference,Prague, July 1 - 8, 2012; JINR preprint Е2-2013-14, Dubna, JINR, 2013. See also A.P.K. and E.A.S., Phys. Rev. C 87 (2013), 024002

Common interest to the lightest nuclei structure at short distances or highrelative 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.

The goal of this talk is to demonstrate that:

Deuteron breakup at 0o 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 informationthan it was extracted so far.

Selected experimental data concerning the deuteron structure

(hadron probes; reminder).

Total cross section for deuteron-proton scattering(intermediate energy region)

Polarization transfer coefficient(from vector polarized deuteron

to proton)

Light cone variable5

Breakup (d,p)X at 0o, backward elastic scattering

Cross section

The key tool: polarized deuteron beams inDubna and Saclay.

Tensor analysing power

Deuteron breakupand the D2 parameter for deuteron

7E.A.Strokovsky, Dubna, 18.03.2013

At small k:

Definition for deuteron in literature:

M – nucleon mass, B – binding energy of deuteron

k in Fm-1

k in GeV/c

Knutson&Haeberli (1976): D2 = (0.432 0.032);W. Gruebler et al (1980): d = (0.0259 0.0007);

= -(22.19 0.82) when k is taken in GeV/c

(Instead of d many people often use notation d).

Dd2 is positive.

Reminder: existing data on deuteron breakup (inclusive)

Zoom atthe next slide

fitDeuteron breakup by protons (Z=1)

Energy range: Tkin=2.1 GeV (Saclay, data tables publ. in 1987 & 1989), 7.4 GeV (Dubna, data tables publ. in 1996)

Knutson&Haeberli (1976): 2D2 = (22.19 0.82) (k in GeV/c)W. Gruebler et al : (1980 ): 2D2 = (24.80 0.67)Our fit of the p(d,p)X data: 2D2 = (23.70 0.33)

Theoretical value of d (or d) is around 0.0254 0.0259;experimental value (averaged) is 0.0256(4); what results in

2D2 = 24.51 0.38Taking 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 T20 at low q (the main interest was to the high q region),

the obtained value is in rather good agreement withexisting 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) .

From V.M.Krasnopol’sky et al, PhL 165B (1985) p.7: Potential: RSC d = 0.0262 2D2 = 25,09

RHC d = 0.0259 2D2 = 24,80

Yale d = 0.0254 2D2 = 24,32

Paris d = 0.0261 2D2 = 24,99

MSU (old) d = 0.0269 2D2 = 25,76From E. Epelbaum, Braz. Journ. Ph., v. 35, p. 854. (2005): N3LO in chiral EFT: d = 0.0254 2D2 = 24,32

d = 0.0255 2D2 = 24,42

From http://nn-online.org/, NN potential by Nijmegen group: Nijm II: d = 0.02521 2D2 = 24,14

Nijm 93: d = 0.02524 2D2 = 24,17

Reid93: d = 0.02514 2D2 = 24,07

Our fit of the p(d,p)X (0o) data: 2D2 = (23.70 0.33)

Effects of the Coulomb interaction(hints)

A.P. KOBUSHKIN, YA.D. KRIVENKO-EMETOV, Ukr. J. Phys. 2008. 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)

Tkin= 7.4 GeV (Dubna, data tables publ. in 1990 & 1996)

(1) deuteron beam polarimetry at intermediate and high energiesboth for tensor polarization

(energy independent, high figure of merit T202!)

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 T20 are (apparently) small.

Conclusions.

Deuteron breakup with spectator proton detection at 0o at momentum in vicinity of pd /2 is very useful reaction for:

Thank you!

Breakup reaction for polarimetry of t ensor polarized deuteron beams

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