Isospin Mixing And In-beam Study Of 56Co Non-yrast States At MLL/Miniball.

Motivation And First Glance On The Results Of The Experiment

Ana Montaner Pizá. Instituto de Física Corpuscular IFIC, Valencia, Spain.

MINIBALL Workshop . 24-25 October 2013. CERN, Geneva.

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Physics motivations Starting point: Comparison of beta decay of 56Zn with its

mirror process 56Fe(3He,t)56Co.

Motivations:1. Study of theγde-excitation of the IAS in 56Co. 2. Clarification of the Jπ assignment of two key levels in 56Co.

At RCNP (Osaka, Japan)

At GANIL (France)

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56Co present knowledge

Present status of the 56Co nucleus from ENSDF  Evaluated Nuclear Structure Data File

3076.0 keV, 1+ ?2635.9 keV, 1+ ?

Isospin mixed states

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Studying the mirror process: Beta decay experiment at GANIL The beta decay experiment was carried out at GANIL in 2010, focused on

the production of 56Zn. (S. Orrigo, B. Rubio, Y. Fujita, W. Gelletly et. al.) The analysis of this experiment is very advanced. In order to fully interpret

this work a better understanding of the 56Co excited states will be crucial. 56Zn → 56Cu + β+

56Zn

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Motivation I: Study of theγde-excitation of the IAS in 56Co

Isospin mixed states

Reference: S.E.A. Orrigo et al., INPC 2013 Proceedings, EPJ Web of Conferences (2013).

• Very low Sp• Proton decay for the IAS

is isospin forbidden gamma de-excitation is possible.

IAS

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Motivation II: Clarification of the Jπ assignment of two key levels in 56Co (1)

The high energy-resolution 56Fe(3He,t)56Co reaction was carried out by Hiro Fujita et. al. at RCNP- Osaka.

According to their results, there exist serious doubts about the 1+ character of the states at 2.633 MeV and 3.073 MeV.

Reference: "Isospin mixing for the isobaric analog state studied in a high-resolution 56Fe(3He,t)56Co reaction". H. Fujita, Y. Fujita et al., submitted to PRC.

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Motivation II: Clarification of the Jπ assignment of two levels in 56Co (2)

Well known 1+

distribution

3.076 MeV

2.633 MeV

2+

distribution

Reference: "Isospin mixing for the isobaric analog state studied in a high-resolution 56Fe(3He,t)56Co reaction". H. Fujita, Y. Fujita et al., submitted to PRC.

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MINIBALL experiment at the MLL (Munich) Experiment carried out in the Maier-Leibnitz-Laboratorium

(MLL) at the Technische Universität München (TUM), in June 2013.

Reaction: 56Fe(p,n)56Co 56Fe Target thicknesses: 1 and 2 mg/cm2

Proton beam: 10 MeV and 12 MeV Beam intensity: 1-3 nA Duration: 6 day Angle calibration reaction: 32S(d,p)33S in inverse kinematics.

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Setup of the experiment

Beam direction

MINIBALL clusters

MINIBALL cluster

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Preliminary results of MINIBALL experiment at MLL

962 keV891 keV

?

962

891869

796

1878

1806

Isospin mixed statesT=1 0+

T=2 0+

IASEither not there or much weaker, and we will get upper limits in due time

1185

Study of theγde-excitation of the IAS in 56Co.

PRELIMINAR

Y

Gated in

the 1185

keV line

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Preliminary results of MINIBALL experiment at MLL (2)

1185 keV peak from the de-excitation of the 2635 keV level:# Counts: 1.12·105

# Counts per measurable angle: 1.12·105/(4x3x6) ≈ 1555

Clarification of the Jπ of the levels 3076 keV and 2636 keV in 56Co using angular correlations.

1185 keV peak

962

891869

796

187

8 180

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Isospin mixed states

T=1 0+T=2 0+

IAS

118

52635.9 keV

480

Miniball: 4 clusters3 crystal/cluster6 segments/crystal

PRELIMINAR

YGated in

the 480 keV

line

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Conclusions

Stability and well behaviour of MINIBALL detectors.

Crosstalk problem. We have to restrict to coincidences between different Clusters.

From the motivation point of view: Angular correlations: we will be able to clarify the spin-

assignment of the 2636 keV and 3076 keV states. Gamma de-excitation of the two 0+ isospin mixed states We

should be able to set meaningful upper limits to those "new" two gamma lines from the de-excitation of the 0+ T=1 state.

ANALYSIS IN PROGRESS. Very preliminary results presented.

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A. Montaner-Pizá, B. Rubio, J. Agramunt, A. Algora, V. Guadilla, S. Orrigo. IFIC-Valencia, Spain.

D. Mücher, S. Reichert, S. Hellgartner, C. Berner. TUM, Munich, Germany.

B. Gelletly. Surrey University, U.K. Y. Fujita. RCNP, Osaka, Japan. E. Ganioglu, Istanbul University, Turkey.

Thank you!