Cross section enhancement in pd reactions at higher energ ｙ K. Sagara, S. Kuroita, T. Sueta, H. Shimoda, Y. Eguchi, K. Yashima, T. Yabe, M. Dozono, Y.

Cross section enhancement in pd reactions at higher energ ｙ

K. Sagara, S. Kuroita, T. Sueta, H. Shimoda, Y. Eguchi , K. Yashima, T. Yabe, M. Dozono, Y. Yamada, T. Wakasa, T. Noro, H. Matsubara *, J. Zenihiro *, Y. Tameshige *, H. Okamura *, A. Tamii *, K. Hatanaka *, T. Saito #, Y. Maeda #, and H. Kamada +

Dept. of Physics, Kyushu University*RCNP, Osaka University#Dept. of Engineering, Miyazaki University+Kyushu Institute of Technology

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3N system

Scattering & Reactions

Bound states

Ay puzzle1986

Ay puzzle

pd CS discrepancy1994-1996-1997

(Sagara discrepancy)

3N BE problem1980’s

3NF(FM)was found

1998pd breakup discrepancy

pd captureAjj anomaly

nnp Space Star anomaly1980’s

higher energy discrepancies

pd sactt. discrepancy

lower energy discrepancies

lower energy discrepancies

ppn Space star anomalyQFS anomaly?

???

???

Discrepancies in 3N systems and their origins

FM-3NF1957

3H binding energy

(Experiment)

8.482MeV

(Theory)

2NF

23NF~1MeV

++

Nd scattering cross section

H.Witala et al. (1998) found that discrepancy in 3N binding energy, and discrepancy in Nd scattering cross section.are removed by including 23NF.

EN= 65 MeV

EN= 140 MeV

23NF

23NF

Ed=140MeVEp= 70MeV

Ed=200MeVEp=100MeV

Ed=270MeVEp=135MeV

Ayd Axz Ayy

Axx

K. Sekiguchi et al.Cross section is reproduced by 23NF, but Analyzing powers are not reproduced.

++ Nd scattering Analyzing Powers

At 250 MeV also, Ay is not reproduced by 23NF or 　 by relativity.

23NF effects relativistic effects

++ Nd scattering Ay at 250 MeV

pd Ay & nd Ayat 250 MeV

pd Ay & nd Ayat 250 MeV

2NF only2NF+3NF

Non-relativisticRelativistic

K.　Hatanaka　et al.,　PRC66　044002(2002)Y.　Maeda　et al.,　PRC76　014004(2007)

At 250 MeV, also cross section is not reproduced. ++

Enhancement　of　backward　cross　section　starts　around　100　MeV.

Cross　Section　at　250　MeV Cross　Section　Ratio　(Exp/Calc)　at150º

150º

= 150 degree

Cross　section　is　　more　basic　quantity　than　analyzing　powers.　

Elastic

Break-up

~5 times

At 250 MeV, break-up reaction is dominant. We investigate enhancement of break-up cross section.

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n+d total reaction cross section

total

GR

LAS

p - beamLiq D2

Target

CS at 250 MeV

Only p1 was detected to see global feature

p1

p2 np1

Our first BU experiment at 250 MeV

CS at 250 MeV Only p1 detected

2NF+3NFOnly　2NF

nd　calc.by　H.　Witala

p2 np1

Cross section

Cross section

Cross section

~1.6 times

Cross SectionExp > Calc

E1

2NF+3NFOnly　2NF

nd　calc.by　H.　Witala

Ay at 250 MeV Only p1 detected

Ay Ay

Ay

AyExp ≠ Calc

p2 np1

E1

CS at 250 MeVp2 np1

p1 and p2 detected (kinematically complete exp.)

P2 detected

P1 detected

Second experiment

Undetected in the first exp.

Microscopic study of CS enhancement.

Configuration space is wide, andMagnetic spectrometers have narrow E-range

find 2-dependence of CS emhance

Select configurations

E1

ABC

A

C

B

1-dependence　at　different　E1

1

p2

p1

We　selected　B,　　E1　=　150　MeV.

Selection　of　E1-range

detected　p1

free

detected　p1

detected　p2

Second experiment

First experiment

2NF+3NF2NF Calc　by　H.　Kamada

2-dependence　　at　E1　=150　MeV,　1　=　15　degree,　and　12　=　180　degree.　

12-dependenceat　E1　=150　MeV,　1　=　15　degree,　and　2　=　35　degree.　

12

2

12

1

Selection　of　2-range

Selection　of　12

GR

LAS

p - beamLiq D2

Target

p1

p2

Cross Section at 250 MeVp2 np1

p1 and p2 detected

Liquid D2 target

True events

BG events

~10mm thickness LD2 [ thick enough]6 m thick window foil [thin enough]“Empty” target easily made for BG run

Low Background level

New　data　were　added　for　p1　detection.　New　and　previous　dara　agree　well

23NF　effects

p2 np1

Same　data.　　　　Relativistic　effects.

Same　data.　　3NF　effects　and　relativistic　effects.

True+BG

BG

Raw　data　at　1　=15　°　and　2　=35　°p2 np1

Check of the absolute cross section using pd elastic scattering cross section

pd scattering

Calc.　by　H.　Witala3NF effects

2NF+3NFOnly　2NF

p2 np1

Calc.　by　H.　Witala

Relativistic effects

RelativisticNon-relativistic

p2 np1

Calculation　by　H.　Witala

3NF　effects　and　relativistic effects

p2 np1

2　dependence　of　BU　cross　section

Systematic uncertainty

p2 np1

degE1=150 MeV

Ep-beam = 250 MeV

~1.6

1

x 5.8

If 3NF effects are artificially 5.8 times increased, experimental CS data are roughly reproduced.

Arb

itra

ry u

nit

Possible　enhancement　of　3NF　at　higher　energy

But, 5.8 times may be too large to explain by 3NF enhance.

Effects of 3NF and/or 3NF?

Summary

At 250 MeV, pd breakup cross section were measured by First, detecting 1-protons from p+d p+p+n reaction, Second, detecting 2-protons in coincidence.

Large discrepancy of about 2 times in CS was observed.The discrepancy was found to appear in a wide angular region.

3NF effects are too small (5.8 time) to explain the discrepancy, also relativistic effects are too small to explain the discrepancy.

CS discrepancy monotonically increases with energy. New 3NF may be necessary to explain the discrepancy.

Ay puzzle1986

Ay puzzle

pd CS discrepancy1994-1996-1997

(Sagara discrepancy)

3N BE problem1980’s

3NF(FM)was found

1998pd breakup discrepancy

pd captureAjj anomaly

nnp Space Star anomaly1980’s

higher energy discrepancies

pd sactt. discrepancy

lower energy discrepancies

lower energy discrepancies

ppn Space star anomalyQFS anomaly?

???

???

Discrepancies in 3N systems and their origins

FM-3NF1957

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