Breakup reaction for polarimetry of t ensor polarized deuteron beams
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Transcript of Breakup reaction for polarimetry of t ensor polarized deuteron beams
Breakup reaction for polarimetry of tensor polarized deuteron beams
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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
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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.
E.A.Strokovsky, Dubna, 18.03.2013
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.
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Selected experimental data concerning the deuteron structure
(hadron probes; reminder).
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Total cross section for deuteron-proton scattering(intermediate energy region)
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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
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Deuteron breakupand the D2 parameter for deuteron
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At small k:
Definition for deuteron in literature:
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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).
E.A.Strokovsky, Dubna, 18.03.2013
Dd2 is positive.
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Reminder: existing data on deuteron breakup (inclusive)
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Zoom atthe next slide
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Excl
uded
from
the
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)
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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) .
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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)
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Effects of the Coulomb interaction(hints)
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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)
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Deuteron breakup by carbon (Z=6)
Tkin= 7.4 GeV (Dubna, data tables publ. in 1990 & 1996)
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(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:
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Thank you!
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