g. macharashvili 2004 - gtu

Analysing power in deuteron breakup

G Macharashvili 2004



First Measurement of the Analyzing Power inpd rarr (pp)n with a Fast Forward 1S0 Diproton



First Measurement of the Analyzing Power in pd rarr (pp)n with a Fast Forward 1S0 Diproton

SYaschenko12 SDymov2 VKomarov2 GMacharashvili23 FRathmann4 SBarsov5 MHartmann4 VHejny4 RGebel4 AKacharava13

AKhoukaz6 PKulessa47 AKulikov2 VKurbatov2 NLang6 ILehmann4 BLorentz4 TMersmann6 SMerzliakov2 SMikirtytchiants5

AMussgiller4 MNioradze3 HOhm4 DPrasuhn4 RSchleichert4 HSeyfarth4 ESteffens1 HJStein4 HStroumlher4 YuUzikov28

BZalikhanov2 and NZhuravlev2

1 PI II Uni Erlangen-Nurnberg Germany 2 JINR Dubna Russia 3 HEPhI TSU Tbilisi Georgia 4 IKP FZ-Julich Julich Germany

5 PNPI Gatchina Russia 6 IKP Uni Munster Germany 7 INPh Krakow Poland 8 KNU Almaty Kazakhstan



Physics motivation

Study of pd dynamics at high momentum transfer Short-range structure of NN interactions

1So ndashstate of the fast forward diproton provides new features absent in the pdrarrdp and exclusive deuteron disintegration

Insight on few nucleon systems at short distances

Different ∆ contribution at 05 and 08 GeV ∆ contribution suppressed by the isospin factor 3 times at 08 GeV

A number of theoretical models proposedLKondratyuk et al Phys Lett B 100 448 (1981)Yu Uzikov Phys Part Nucl 29 (1998) 583LPKaptari et al Eur Phys J A19 301 (2004) hellip



Range telescopeswith TOF-Stop ∆E

Cluster-jet

Target

D1

D2

D3

TOF-start

MWPC 12

1 m

1 23

COSYbeam

NIM A 462 364 (2001)

Side walldetectors

Forwarddetectors

Backwarddetectors

Negative particledetectors

NIM A 481 378 (2002)

ANKE spectrometer

ANKE spectrometer



Polarizaed proton beamstored in COSY ring 3 109

polarization 0564 plusmn 0003stat plusmn 0004syst

D2 cluster targetdensity 21014 cm-2

along the beam 12 mmfull width 45 mm



Forward detector acceptance



Spectator detector (SDT) Energy resolution 300 keV

Momentum [GeVc]1 12 14 16 18 2


Num

ber o

f eve

nts

1

10

210

310

Proton momentum in FD for detected in SDT deuteronsNo background hellip

These elastic events were used for beam polarimetry



Polarization export

-Spin flip occures at 6318 MeV(the 2nd improper resonanse)

-depolarization caused bymagnetic field errorsmisalignment of magnetsvertical focussing magnets

-Polarization loss is less than 1

ALehrach et al Spin-2002 p153

No loss of the beam polarization during the polarization export



Beam polarimetry at 08 GeV

Analysing power in pd elastic scattering is used for the beam polarization measurement in the 1st and the 3rd flattops The Polarization value is exported to the 2nd flattop at 05 GeV

Exp data fromFIrom et al PhysRevC 28 2380 (1983)



Analysis procedure

minus Double-track events are filtered for proton-pair selection

minus The efficiency of double-proton identification is checked by ∆E and TOF difference methods

minus Two proton phase space was checked

minus LeftRight scattered events were accumulated



Two particle momentum correlation

Break-up events are concentrated at the outer arc center



Two particle TOF differences(measured versus calculated)

For the calculation two-protonhypothesis was used

(pp) ndash on the diagonal(dππππ++++) (dp) (pππππ++++) (tππππ++++) identified

TOF measurement uncertainty(the diagonal profile RMS)200 ps at 05 GeV180 ps at 08 GeV



Missing-mass spectra

Proton-pair selection criteriaEpplt 3 MeVcosϕϕϕϕ gt 07gt 07gt 07gt 07||||YYYYtargettargettargettarget| lt 22 cm| lt 22 cm| lt 22 cm| lt 22 cm

Background in plusmn3σσσσσσσσ interval05 GeV 5 08 GeV 13



Ay calculation and statistical uncertainties

Leftright counts of the break-up events were accumulated in each θbin

L(θ) ~ X+ (1 + Ay (θ) P+ ltcosφgt)R(θ) ~ Xminus (1 minus Ay (θ) Pminus ltcosφgt)

Measured asymmetryε(θ) = ( L(θ) minus f R(θ) ) (L(θ) + f R(θ) )

Where f is the relative luminosity correction factor f = X+Xminus

Statistical uncertaintyδε = (L + fR)-1 [(1 ndash ε2)L + (1 + ε2)(f2R + δf

2R2)]frac12

Finally the analysing power is defined asAy(θ) = ε(θ) P ltcosφgtθ P = 05 (P+ + Pminus)



Systematic uncertainties

Difference of the beam polarizationP = 05 (P+ + Pminus)

∆P = 05 (P+ minus Pminus)leads to the change of analysing powerAy rarr Arsquoy = Ay (1 + ∆PmiddotAy)-1

Relative luminosity correction factor f = L +L -if frarrfrsquo = f (1 + ξ)Ay rarr Arsquoy lt Ay ndash ξ2P

Systematic uncertainties are negligible in comparisonwith statistical ones (le 002)



Realtive luminosity monitoring

For relative luminosity monitoring the polarizationindependent count rates used

Single protons counted at polar angles close to zero θcm lt 1o

Single protons counted at azimuthal angles85o lt φ lt 95o or 265o lt φ lt 275o



θ

θ

ppcm

ncm

p

p

1

2

p1

p2

θ kcm

(pp)

(pp)

p

nd

center-of-mass frame proton-pair rest frame

Selected event cosθkkkkcmcmcmcm distributions

S ndash wave dominance




Excitation energy spectra

Events accepted ifEpp lt 3 MeV and cosϕϕϕϕ gt 07gt 07gt 07gt 07

Epp uncertainty (RMS)



Angular dependence of the analysing power Ay asa function of back-scattered neutron cm angle

About 2800 and 2200 break-up events were collected at 05 and 08 GeV respectively



SummaryThe analysing power in the deuteron break-up was measured at two beam energies of 05 and 08 GeVat proton-pair sacttering angles 0o lt θcm lt 14o

The model accounting ONE SS and ∆ excitationdescribes well the unpolarized break-up cross section[VKomarov et al PhysLett B 553 179 (2003)]

The model fails to reproduce large Ay at 05 GeV

New approach is required





First Measurement of the Analyzing Power inpd rarr (pp)n with a Fast Forward 1S0 Diproton












Physics motivation









Cluster-jet

Target

D1

D2

D3

TOF-start

MWPC 12

1 m

1 23

COSYbeam

NIM A 462 364 (2001)

Side walldetectors

Forwarddetectors

Backwarddetectors


NIM A 481 378 (2002)

ANKE spectrometer

ANKE spectrometer















Num

ber o

f eve

nts

1

10

210

310





Polarization export













Analysis procedure




























2R2)]frac12

















θ

θ

ppcm

ncm

p

p

1

2

p1

p2

θ kcm

(pp)

(pp)

p

nd

































Physics motivation









Cluster-jet

Target

D1

D2

D3

TOF-start

MWPC 12

1 m

1 23

COSYbeam

NIM A 462 364 (2001)

Side walldetectors

Forwarddetectors

Backwarddetectors


NIM A 481 378 (2002)

ANKE spectrometer

ANKE spectrometer















Num

ber o

f eve

nts

1

10

210

310





Polarization export













Analysis procedure




























2R2)]frac12

















θ

θ

ppcm

ncm

p

p

1

2

p1

p2

θ kcm

(pp)

(pp)

p

nd

























Cluster-jet

Target

D1

D2

D3

TOF-start

MWPC 12

1 m

1 23

COSYbeam

NIM A 462 364 (2001)

Side walldetectors

Forwarddetectors

Backwarddetectors


NIM A 481 378 (2002)

ANKE spectrometer

ANKE spectrometer















Num

ber o

f eve

nts

1

10

210

310





Polarization export













Analysis procedure




























2R2)]frac12

















θ

θ

ppcm

ncm

p

p

1

2

p1

p2

θ kcm

(pp)

(pp)

p

nd




































Num

ber o

f eve

nts

1

10

210

310





Polarization export













Analysis procedure




























2R2)]frac12

















θ

θ

ppcm

ncm

p

p

1

2

p1

p2

θ kcm

(pp)

(pp)

p

nd
























Polarization export













Analysis procedure




























2R2)]frac12

















θ

θ

ppcm

ncm

p

p

1

2

p1

p2

θ kcm

(pp)

(pp)

p

nd





























Analysis procedure




























2R2)]frac12

















θ

θ

ppcm

ncm

p

p

1

2

p1

p2

θ kcm

(pp)

(pp)

p

nd













































2R2)]frac12

















θ

θ

ppcm

ncm

p

p

1

2

p1

p2

θ kcm

(pp)

(pp)

p

nd





































θ

θ

ppcm

ncm

p

p

1

2

p1

p2

θ kcm

(pp)

(pp)

p

nd






















g. macharashvili 2004 - gtu

Documents