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Measurements of inclusive pd-breakup cross section at low and ...

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The contents <strong>of</strong> today’s talk<br />

★ D(p,p)pn <strong>at</strong> Ep = 248 MeV<br />

★ D(p,p)pn <strong>at</strong> Ep = 13 MeV<br />

S. Kuroita a , K. Sagara a , T. Kudoh a , T.Sueta a , T. Sugimoto a , H. Shimoda a<br />

Y. Yamada a , T. Wakasa a , T. Noro a , Y. Tameshige b , A. Tamii b , K. H<strong>at</strong>anaka b<br />

a<br />

: Department <strong>of</strong> Physics, Kyushu University<br />

b<br />

: Research Center for Nuclear Physics (RCNP)<br />

1


• Cross <strong>section</strong> <strong>of</strong> dp elastic sc<strong>at</strong>tering <strong>at</strong> 135MeV/A agrees well with Faddeev<br />

calcul<strong>at</strong>ions with 2π3NF.<br />

• Cross <strong>section</strong>s <strong>of</strong> <strong>pd</strong> <strong>and</strong> nd elastic sc<strong>at</strong>tering <strong>at</strong> 250MeV <strong>at</strong> backward angles<br />

disagree with Faddeev calcul<strong>at</strong>ions with 2π3NF.<br />

135 MeV 250 MeV<br />

K. Sekigchi et al. PRC65, 034004(2002) K. H<strong>at</strong>anaka et al. PRC66, 044002(2002)<br />

Y. Maeda et al. PRC76, 014004 (2007)<br />

2


• At intermedi<strong>at</strong>e eneregy<br />

• <strong>pd</strong> <strong>breakup</strong> <strong>cross</strong> <strong>section</strong> is several times lager than <strong>pd</strong> elastic sc<strong>at</strong>tering<br />

<strong>cross</strong> <strong>section</strong>,<br />

σ tot<br />

J. Kuros‐Zoluierczuk et al.<br />

PRC66, 024003(2002)<br />

σ <strong>breakup</strong><br />

σ elastic<br />

• There are many experiments on <strong>pd</strong> sc<strong>at</strong>tering, but there are few experiments<br />

on <strong>pd</strong> <strong>breakup</strong>.<br />

3


• To see global fe<strong>at</strong>ure <strong>of</strong> <strong>pd</strong> <strong>breakup</strong> reaction, <strong>inclusive</strong> measurements <strong>of</strong><br />

D(p,p)pn are better than exclusive measurements <strong>of</strong> D(p,pp)n.<br />

• Calcul<strong>at</strong>ions by H. Witala indic<strong>at</strong>e th<strong>at</strong> FSI peak <strong>cross</strong> <strong>section</strong> <strong>at</strong> 10 degree is<br />

about 1.5 times enhanced by 2π3NF effects.<br />

pn FSI<br />

FSI peak<br />

pp FSI<br />

4


• Observables : <strong>cross</strong> <strong>section</strong>, Ay<br />

• Target : Liq.D2(~150mg/cm 2 )<br />

CD2, GD2(gas D2)<br />

• Angle : 7, 10, 15, 20 degrees (lab)<br />

Wide energy range was covered by<br />

4‐momentum‐range measurements.<br />

5


• D<strong>at</strong>a <strong>at</strong> 4‐momentum regions were smoothly connected.<br />

• Even <strong>at</strong> FSI peak, LD2 events were larger than GD2 events by about 6 times.<br />

True events + BG events Only BG events<br />

θ=20deg<br />

10 times<br />

FSI<br />

LD 2 target<br />

True events<br />

GD 2 target<br />

(BG)<br />

7


• A homogeneous CD2 target <strong>of</strong> 10mg/cm 2 in thickness was made, <strong>and</strong> the<br />

thickness was precisely measured using 12MeV <strong>pd</strong> sc<strong>at</strong>tering <strong>at</strong> KUTL.<br />

• LD2 target thickness was determined by comparing D(p,p)d events from the<br />

LD2 target <strong>and</strong> CD2 target.<br />

• Using the determined LD2 target thickness, we obtained <strong>pd</strong> sc<strong>at</strong>tering <strong>cross</strong><br />

<strong>section</strong>. The <strong>cross</strong> <strong>section</strong> agreed well with K. H<strong>at</strong>anaka’s d<strong>at</strong>a.<br />

LD2 target<br />

D(p,p)d<br />

CD2 target<br />

D(p,p)d<br />

8


High‐st<strong>at</strong>istic & smooth d<strong>at</strong>a were obtained.<br />

Large disagreement was found.<br />

2NF+3NF<br />

2NF only<br />

Calc. by H. Witala<br />

9


7deg<br />

10deg<br />

15deg<br />

20deg<br />

Calc. by H. Witala 10


Calc. by A. Deltuva<br />

11


7deg<br />

10deg<br />

15deg<br />

20deg<br />

Calc. by A. Deltuva 12


Calc. by H. Witala<br />

13


7deg<br />

10deg<br />

15deg<br />

20deg<br />

Calc. by H. Witala<br />

14


Calc. by A. Deltuva<br />

15


7deg<br />

10deg<br />

15deg<br />

20deg<br />

Calc. by A. Deltuva 16


• We measured <strong>cross</strong> <strong>section</strong> <strong>and</strong> Ay <strong>of</strong> D(p,p)pn <strong>at</strong> 248MeV <strong>at</strong> 7º‐20º <strong>at</strong><br />

RCNP. The d<strong>at</strong>a were compared with 3N calcul<strong>at</strong>ions by Witala et al. <strong>and</strong><br />

Deltuva et al.<br />

• Cross <strong>section</strong> is 1.5‐3 times larger than 3N calcul<strong>at</strong>ions.<br />

• Ay is considerably larger than 3N calcul<strong>at</strong>ions.<br />

• The disagreement in <strong>cross</strong> <strong>section</strong> <strong>and</strong> Ay increases <strong>at</strong> forward angle.<br />

• Inclusion <strong>of</strong> 2π3NF or Δ‐isobar increases <strong>cross</strong> <strong>section</strong> by 30‐50%, <strong>and</strong><br />

decreases Ay slightly.<br />

• Coulomb force slightly decreases <strong>cross</strong> <strong>section</strong> <strong>and</strong> has little effects on Ay.<br />

• Even after inclusion <strong>of</strong> 2π3NF or Δ‐isobar <strong>and</strong> Coulomb force, large<br />

disagreement remains in <strong>cross</strong> <strong>section</strong> <strong>and</strong> Ay.<br />

• 3NF other than 2π3NF <strong>and</strong> rel<strong>at</strong>ivistic effect should be investig<strong>at</strong>ed.<br />

17


• At <strong>low</strong> energy,<br />

• The effects <strong>of</strong> 3NF (2π3NF <strong>and</strong> other 3NF) are small, <strong>and</strong> rel<strong>at</strong>ivistic effects<br />

are also small.<br />

• There is Star Anomaly (Sagara’s talk) <strong>at</strong> special kinem<strong>at</strong>ic configur<strong>at</strong>ions.<br />

• Coulomb effects are large, but <strong>pd</strong> calcul<strong>at</strong>ions by Deltuva et al are now<br />

available.<br />

• We made D(p,p)pn experiment <strong>at</strong> 13MeV using a t<strong>and</strong>em acceler<strong>at</strong>or <strong>at</strong> KUTL,<br />

to see the fol<strong>low</strong>ings:<br />

• Whether the disagreement found <strong>at</strong> 248MeV disappears <strong>at</strong> 13MeV or not ?<br />

• Whether Star anomaly has any effects on <strong>inclusive</strong> <strong>cross</strong> <strong>section</strong> or not ?<br />

18


• Beam : 13 MeV p‐beam <strong>of</strong> 200nA<br />

• Target : D 2 gas <strong>of</strong> 0.5‐0.8 bar, 2.2mm thick Havar foils for beam windows<br />

• Detectors : ΔE‐E counter telescope <strong>of</strong> Si‐SSD (p/d separ<strong>at</strong>ion), double‐slit system<br />

• Angular range : 10º‐70º in 5º‐10º step<br />

• Severe backgrounds : continuum protons produced by beam halo were cut by<br />

buffer slits.<br />

• The figure show D 2 gas target cell used <strong>at</strong> 10º‐20º. Continuum protons produced<br />

<strong>at</strong> the beam defining slit must sc<strong>at</strong>tered twice <strong>at</strong> walls <strong>and</strong> once <strong>at</strong> the window foil<br />

to come to detectors.<br />

19


• Continuum BG produced by D2 gas were estim<strong>at</strong>ed from BG produced<br />

by H2 gas.<br />

• The estim<strong>at</strong>ed (D2 gas BG + vacuum BG) were subtracted from spectrum<br />

measured with D2 gas.<br />

20deg<br />

20


nd calc.<br />

<strong>pd</strong> calc.<br />

Calc. by A. Deltuva<br />

21


Calc. by A. Deltuva<br />

22


• We measured <strong>inclusive</strong> D(p,p)pn <strong>cross</strong> <strong>section</strong> <strong>at</strong> 13 MeV in wide angular range<br />

<strong>of</strong> 10º‐70º deg <strong>at</strong> KUTL.<br />

• We used a improved gas target cell to reduce continuum‐energy proton<br />

backgrounds which are gener<strong>at</strong>ed by beam halo.<br />

• The measured <strong>cross</strong> <strong>section</strong> was compared with <strong>pd</strong> calcul<strong>at</strong>ions by Deltuva et al.<br />

• D(p,p)pn <strong>cross</strong> <strong>section</strong> <strong>at</strong> 13 MeV in whole the angular range is well<br />

reproduced by the <strong>pd</strong> calcul<strong>at</strong>ion.<br />

• There is no large disagreement in global fe<strong>at</strong>ure <strong>of</strong> <strong>pd</strong> <strong>breakup</strong> <strong>cross</strong> <strong>section</strong><br />

<strong>at</strong> <strong>low</strong> energy.<br />

23


• At 13MeV, D(p,p)pn <strong>cross</strong> <strong>section</strong> agree well with <strong>pd</strong> calcul<strong>at</strong>ion.<br />

• At 248MeV, D(p,p)pn <strong>cross</strong> <strong>section</strong> <strong>and</strong> Ay largely disagree with calcul<strong>at</strong>ions.<br />

• Possible origin <strong>of</strong> the disagreement <strong>at</strong> 248MeV may be effects <strong>of</strong> 3NF other than<br />

2π3NF <strong>and</strong>/or rel<strong>at</strong>ivistic effects.<br />

• We need several experiments to investig<strong>at</strong>e the origin.<br />

• Measurement <strong>of</strong> D(p,p)pn <strong>cross</strong> <strong>section</strong> <strong>at</strong> 100‐200MeV where <strong>pd</strong> elastic<br />

sc<strong>at</strong>tering <strong>cross</strong> <strong>section</strong> is well reproduced by calcul<strong>at</strong>ions with 2π3NF.<br />

To see energy dependence <strong>of</strong> the disagreement.<br />

• Measurement <strong>of</strong> “exclusive” D(p,pp)n <strong>cross</strong> <strong>section</strong> <strong>at</strong> 248MeV<br />

To investig<strong>at</strong>e origin <strong>of</strong> the disagreement in various<br />

kinem<strong>at</strong>ical configur<strong>at</strong>ions.<br />

24


As this figure show, yields using<br />

Liq.D2 Is larger than ones using CD2<br />

by maximum 2 order.<br />

26


• Cross <strong>section</strong><br />

Calc. by H. Witala<br />

27


• Analyzing power Ay<br />

Calc. by H. Witala<br />

28


• Cross <strong>section</strong><br />

29


• Analyzing power Ay<br />

30


• Continuum BG were composed <strong>of</strong> BG in vacuum target <strong>and</strong> BG produced<br />

by D2 gas.<br />

• BG produced by H2 <strong>and</strong> BG produced by 4He were nearly the same.<br />

• So we assumed th<strong>at</strong> H2, D2, 4He gases produces nearly the same BG <strong>and</strong><br />

we estim<strong>at</strong>ed BG produced by D2 gas from BG produced by H2 gas.<br />

31


• BG spectra were measured using vacuum, hydrogen, helium <strong>and</strong> air targets.<br />

• BG from a hydrogen target were a little higher than ones from a vacuum, So we<br />

assumed th<strong>at</strong> BG from deuterium gas target is the same as ones from a<br />

hydrogen target <strong>of</strong> the same pressure, <strong>and</strong> made BG subtraction.<br />

BG(D 2 ) ≒BG(H 2 )<br />

32

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