Search for qfs anomaly in pd breakup reaction below e p 19 mev
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Search for QFS anomaly in pd - breakup reaction below E p = 19 MeV. Shuntaro Kimura, K. Sagara, S. Kuroita, T. Yabe, M. Okamoto, K. Ishibashi, T. Tamura, S. Tanaka, Y. Maeda 1 , Y. Ooishi 2 , Y. Ishibashi 2 , A. Ozawa 2 , Y. Tagishi 2 and T. Komatsubara 2

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Search for QFS anomaly in pd - breakup reaction below E p = 19 MeV

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Search for qfs anomaly in pd breakup reaction below e p 19 mev

Search for QFS anomalyin pd-breakup reaction below Ep=19 MeV

Shuntaro Kimura,

K. Sagara, S. Kuroita, T. Yabe, M. Okamoto,

K. Ishibashi, T. Tamura, S. Tanaka,

Y. Maeda1,

Y. Ooishi2, Y. Ishibashi2, A. Ozawa2,

Y. Tagishi2 and T. Komatsubara2

Department of Physics, Kyushu University,

1 Department of Applied Physics, University of Miyazaki,

2 Department of Physics, University of Tsukuba


Anomalies in n d p d n d reactions

Anomalies in N+d (p+d & n+d) reactions

  • Low energy region below about 30 MeV

    • Ay

    • s

    • s

reaction

Anomaly

#1. Space Star anomaly (s)

#2. Quasi-Free Scattering anomaly (s)

< APFB2011 >


1 space star anomaly review

#1. Space Star anomaly (review)

  • Low energy region in pd-breakup reaction

    • Space Star anomaly is well-known.

● TUNL (1996)

13 MeV

Space Star configurationin pd-breakup reaction

○ Erlangen (1989)

■ KUTL (2002)

nd exp. > nd calc.

□ Koeln (1991)

+30%

a=90°

pd exp. < pd calc.

-15%

c.m. system

Space Star

Calc. by A. Deltuva et al. (2005)

< APFB2011 >


1 space star anomaly review1

#1. Space Star anomaly (review)

  • a-dependence of Star cross section

a= 90°

13 MeV

Space Star

s (exp.) / s (calc.)

Anomaly appears around a= 90°

Energy dependence of SS anomaly

○ Erlangen (89’, 93’)

△ TUNL (96’, 01’, 05’)

◇ Bochum (1989)

○ Koeln (91’, 96’)

a [deg]

― CDB

SS anomaly in pd-breakup was confirmed.

Origin of SS anomaly is not known.

< APFB2011 >


2 quasi free scattering qfs anomaly

#2. Quasi-Free Scattering (QFS) anomaly

  • Low energy region in pd-breakup reaction

    • QFS anomaly has been also reported from some experiments.

pp-QFS

nn-QFS

Lab system

Lab system

19 MeV

26 MeV

2002

@ Bonn

1996

@ Koeln

< APFB2011 >


2 energy dependence of qfs anomaly

#2. Energy dependence of QFS anomaly

  • Energy dependence of QFS cross section

  • QFS anomaly has similarities with SS anomaly.

    • Anomalies in cross section

    • Charge asymmetry

  • Origin of QFS anomaly is also not known.

nd exp. > nd calc.

s (exp.) / s (calc.)

□ CIAE (2007)

○ Bonn (2002)

□ Koeln (72’, 91’, 96’)

pd exp. < pd calc.

○ Grenoble (1972)

Energy [MeV]

< APFB2011 >


Motivation

Motivation

  • This time, we measured pp-QFS cross sections.

  • Reasons (We chose pp-QFS)

    • E-dependence has not been established.

    • Experimental precision (pd > nd )

    • Reliable pd calculation by

      A. Deltuva et al (2005) becomes available.

  • Our strategy

    ① Systematic and precise experiments on pp-QFS cross section.

    ② Compare the data with the reliable pd calculation.

    ③ Confirm whether pp-QFS anomaly is true or not.

nn-QFS

pp-QFS

< APFB2011 >


Previous experiments @ kutl

[Ⅰ] Previous experiments @ KUTL

  • We measured pp-QFS cross sections at 9.5 & 13 MeV.

  • Contrary to Koeln group that used a polarized beam,

    we used an unpolarized proton beam in tandem accelerator lab (KUTL).

    • In order to measure ONLY cross section.

13

pp-QFS

9.5

Lab system

< APFB2011 >


Previous experimental results

[Ⅰ] Previous experimental results

  • 9.5 & 13 MeV pp-QFS cross sections (at q1= q2)

Result at 9.5 MeV

Result at 13 MeV

QFS

QFS

< APFB2011 >


Previous experimental results1

[Ⅰ] Previous experimental results

  • Energy dependence of QFS cross section

13

q1= q2

□ CIAE (2007)

9.5

○ Bonn (2002)

s (exp.) / s (calc.)

□ Koeln (72’, 91’, 96’)

Next

○ Grenoble (1972)

● KUTL (2009)

Additional experiments

Change the detection angle

Energy [MeV]

q1< q2

< APFB2011 >


Previous experimental results2

[Ⅰ] Previous experimental results

  • 13 MeV pp-QFS cross sections (at q1= q2, q1< q2).

13 MeV

q 1< q 2

q 1 = q 2

q2 [deg]

QFS

exp. / calc.

q1 [deg]

< APFB2011 >


Previous experimental results3

[Ⅰ] Previous experimental results

  • 9.5 MeV pp-QFS cross sections (at q1= q2, q1< q2).

9.5 MeV

q 1< q 2

q 1 = q 2

q2 [deg]

exp. / calc.

QFS

q1 [deg]

< APFB2011 >


Previous experimental results4

[Ⅰ] Previous experimental results

  • pp-QFS cross sections at several detection angles (at q1= q2, q1< q2)

    agreed with the pd calculation.

  • We confirmed there is no pp-QFS anomaly at 9.5 & 13 MeV.

exp. / calc.

exp. / calc.

< APFB2011 >


Present experiment

[Ⅱ] Present experiment

  • Energy dependence of QFS cross section

  • We confirmed there is no anomaly at 9.5 & 13 MeV.

  • In our present experiment, we measured pp-QFS cross section at 19 MeV.

NEXT

19

< APFB2011 >


Experimental procedure at 19 mev

[Ⅱ] Experimental procedure at 19 MeV

  • Facility : Accelerator center @ University of Tsukuba

  • Beam : 19 MeV unpolarized proton beam ( ~ 150 nA)

  • Target : CD2 foil ( ~ 0.4 mg/cm2) mounted on a rotary target

  • Detectors : Si-SSD

  • Observable : Differential cross section

    of the 2H(p,pp)n reaction on pp-QFS

  • Detection angle : (q1, q2, Δf12)=(41.0°, 41.0° , 180.0°)

pp-QFS

Lab system

< APFB2011 >


Setup in scattering chamber

[Ⅱ] Setup in scattering chamber

  • - coincident detection

    • We measured E1, E2, T2-T1.

  • Monitor → Detect pd-elastic scattering events simultaneously.

E1

E2

< APFB2011 >


Strong points

[Ⅱ] Strong points

  • ① We used an unpolarizedp-beam in order to measure ONLY cross section.

  • ② We mounted a CD2 foil on a rotary target.

    • More stable measurement than

      a fixed target.

p-beam

① Unpolarized beam

② Rotary target

Rotary

Thickness [mg/cm2]

Fixed

Time [h]

< APFB2011 >


Strong points1

[Ⅱ] Strong points

  • ③ We used well-defined apertures for the housings of detectors.

    • Precise determination of each solid angle

③ Well-defined apertures

① Unpolarized beam

② Rotary target

Ordinary mechanical machining edge

Electric discharge machining edge

Aperture

Smooth

Not smooth

< APFB2011 >


Data analysis

[Ⅱ] Data analysis

pd-breakup cross section

Raw data

19 MeV

● present

E2 [MeV]

S

S [MeV]

S = 0

E1 [MeV]

S : arc length from S=0 point

< APFB2011 >


Time of flight tof method

[Ⅱ] Time-of–Flight (TOF) method

True+B.G. gate

True+B.G.

Raw data

Counts/0.5 MeV

True+ B.G.

E2 [MeV]

E2 [MeV]

S

S

B.G.

S = 0

S = 0

B.G. only gate

S [MeV]

E1 [MeV]

E1 [MeV]

Remove B.G.

B.G.only

pd-breakup events

T(E2)–T(E1) [ns]

E2 [MeV]

Counts/0.5 MeV

True

S = 0

T2–T1 [ns]

S [MeV]

E1 [MeV]

Li : distance from target to detector

< APFB2011 >


Determination of absolute value

[Ⅱ] Determination of absolute value

pd-breakup cross section

pd-breakup events

Estimate

pd-breakup cross section

Monitor

pd-elastic cross section

0.5 MeV

pd-elastic scattering events

Geometrical measured

・Distance

(From target to detector)

・Aperture size

Counts/Channel

From experimental data

(K. Sagara et al (1994))

Channel

< APFB2011 >


Present experimental result at 19 mev

[Ⅱ] Present experimental result at 19 MeV

  • 19 MeV pp-QFS cross section

    • Total systematic error is about ±4%.

    • Experimental data shows a good agreement with the pd calculation.

  • Systematic errors

    • Monitor cross section : ±0.3%

    • Solid angles

      • Monitor SSD : ±0.3%

      • Breakup SSD : ±2.3%

    • pd-elastic events : ±2 %

    • Others : ±1 %

  • Total error about : ±4 %

● present

19 MeV

○ Koeln

― pd

pd+Δ

nd

QFS

S [MeV]

Calc. by A. Deltuva et al. (2005)

< APFB2011 >


Present experimental result at 19 mev1

[Ⅱ] Present experimental result at 19 MeV

  • Energy dependence of QFS cross section

  • We conclude there is no pp-QFS anomaly at 19 MeV.

    • We guess there is also no pp-QFS anomaly at 16 MeV.

  • We measured a cross sectionat 7.5 MeV.

19 MeV

19

13

□ CIAE (2007)

9.5

○ Bonn (2002)

s (exp.) / s (calc.)

□ Koeln (72’, 91’, 96’)

QFS

○ Grenoble (1972)

7.5

● KUTL (2009)

Preliminary

● KUTL (Present)

Calc. by A. Deltuva et al. (2005)

Energy [MeV]

< APFB2011 >


Preliminary experimental result at 7 5 mev

[Ⅱ] Preliminary experimental result at 7.5 MeV

  • 7.5 MeV pp-QFS cross section

    • Statistical error is about ±3%.

    • Experimental data shows an almost good agreement with the pd calculation.

● preliminary

7.5 MeV

― pd+D

pd

QFS

S [MeV]

Calc. by Ishikawa

< APFB2011 >


Summary

Summary

  • We made systematic measurements on pp-QFS cross section,

    previously at 9.5 & 13 MeV, recently at 19 & 7.5 MeV.

  • We compared the data with the pd calculation by A. Deltuva et al (2005).

  • From our experiments,

    • All of the results show good agreements with the pd calculation.

    • There are no pp-QFS anomaly at 7.5, 9.5, 13, and 19 MeV

      contrary to pd SS anomaly around 30 MeV.

  • We guess

    • No pp-QFS anomaly at 16 MeV, and

      also at higher incident energies.

  • We have not known

    whether nn-QFS anomaly is true or not.

< APFB2011 >


Comparison of experimental conditions

Comparison of experimental conditions

19 MeV

< APFB2011 >


Comparison of cd bonn av18

Comparison of CD-Bonn & AV18

7.5 MeV

~4%

13 MeV

9.5 MeV

19 MeV

~4%

~2%

By A. Deltuva, CD-Bonn

By Ishikawa, AV18

< APFB2011 >


Search for qfs anomaly in pd breakup reaction below e p 19 mev

19

13

□ CIAE (2007)

9.5

○ Bonn (2002)

s (exp.) / s (calc.)

□ Koeln (72’, 91’, 96’)

○ Grenoble (1972)

7.5

● KUTL (2009)

● KUTL (Present)

Energy [MeV]

< APFB2011 >


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