SEARCH FOR RARE CLUSTER CONFIGURATION IN 14C

NUCLEUS

International Conference on Particle Physics and AstrophysicsOctober 05 – 10, 2015

L.Yu. Korotkova, B.A. Chernyshev, Yu. B. Gurov, S.V. Lapushkin, R.V. Pritula, T.D. Schurenkova

National Research Nuclear National Research Nuclear UniversityUniversity “ “MEPhI”MEPhI”

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SStudy of mechanisms of stopped pion absorption by light nuclei;

SSearch for rare cluster configurations in light nucleus (1414CC);

SSearch for new highly excited states of 12,1312,13BeBe isotopes and

their rare cluster decays;

SSpectroscopy of the 1111LiLi halo nucleus

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Main Main goals :goals :

1414C cluster structureC cluster structure• AMD model prediction: 1414C = C = 1212C + 2n = 3C + 2n = 3αα + 2n + 2n [1]• For the excited states of 14C : 1414C = C = 1010Be + Be + αα [2]

What if What if 1414C = C = 1111Li + 3pLi + 3p ??????

99Li + 2nLi + 2n

[1] T. Suhara and Y. Kanada-En’yo // Journ. of Phys.: Conf. Ser. 321 (2011) 012047[2] P. J. Haigh et al. // Phys. Rev. C 78 (2008) 014319. 3

Advantages of the method:

Formation of residual nuclei with large neutron excessAbsence of uncertainties due to the energy resolution and angular divergence of beamAbility to study a wide range of nuclei in a single experimental run

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3-body channels3-body channels of the stopped pion of the stopped pion absorption by nucleiabsorption by nuclei

Beam Targets : 12C & 14C Rate speed

1/s

SCD- telescope Start identification energy,

MeV

Е = 30 MeV(p/p = 1%)

Thickness – 25 mg/sm2, (135µm), diameter – 26mm, 14C target: 14C – 77%, 12C – 23% 12C – impurities < 1%

610**4

2 Si(Au) Т=100, 450 µm14 Si(Li) Т=3 mm, Wm.s.0.1mm S=8 mm2

=5515 mster

Еp 3.5, Еd 4

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Setup Setup (LANL)(LANL)

2-dim Dalitz-plot for 11В(π,dt)Х reaction

1111В В = = 55LiLi +  + 66HeHe

1.1. 1111B(π¯,B(π¯,ddt)t)66HeHe andand 1111B(π¯,B(π¯,ddt)t)66HeHe** ЕЕхх((66Не*) = 1.797 Не*) = 1.797 MeVMeV 2. and 3. 2. and 3. π¯ + π¯ + 1111В → В → dd + + 88LiLi* + * + nn → → dd + + tt + + 55HeHe + + nn ЕЕхх((88LiLi*) = 10.822 *) = 10.822 MeVMeV ( (22) ) and and ЕЕхх((88LiLi*) = 6.53 *) = 6.53 MeVMeV ((33). ). 4. 4. π¯ + π¯ + 1111В → В → tt + + 77LiLi* + * + nn → → tt + + dd + + 55HeHe + + nn ЕЕхх((77LiLi*) = *) =

11.2411.24 MeV MeV6

1111ВВ((ππ,,dtdt))ХХ

Nucleus-2013, MoscowNucleus-2013, MoscowYu.B. Gurov et al. // BRAS: Yu.B. Gurov et al. // BRAS: Phys. Phys. 7979 (2014) 474. (2014) 474.

Cluster structure of Cluster structure of 1111ВВ

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1212CC admixture in the admixture in the 1144C targetC target

Experimental spectrum (dots with errors) with the 12C admixture contribution (blue histogram)

Experimental spectrum after the subtraction of the 12C admixture contribution

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2-dim Dalitz-plot for 14C(π,pd)Х reaction

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3

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1. 14C(π¯,pd)11Li and 14C(π¯,pd)11Li*

2. π¯ + 14C → p + 13Be*

d + 11Li3. π¯ + 14C → d + 12Be*

p + 11Li

1414C = C = 33p + p + 1111LiLiexotic cluster structureexotic cluster structure ”11Li – spectator” momentum

distribution

F(р) = (p/pF)2 exp(–(p/pF)2)

Search for rare cluster Search for rare cluster structurestructure

9Bohlen H.G. et al. // Z. Physik A 351 (1995) 7

Korsheninnikov A.A. et al. //Phys. Rev. Lett. 78 (1997) 2317

Current experimental situation: Current experimental situation: 1111LiLi J.H. Kelley et al. // NP

A 880 (2012), 88

Er, MeV τ, ms or Г, MeV Reaction / Paper

g.s. 8.75 ± 0.14 ms [1], 14C(π−, pd)Х0.9 ± 0.1 ~ 0.3 14C(π−, pd)Х

1.22 ± 0.04 0.53 ± 0.15 [1]2.3 ± 0.3 ~ 0.7 14C(π−, pd)Х

2.42 ± 0.05 1.26 ± 0.30 [1]3.9 ± 0.3 < 0.2 14C(π−, pd)Х

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1144CC((,, pd pd))1111Li Li

[1] Kelley J.H. et al. // Nucl. Phys. A 880 (2012) 88

MM spectrum for the 1144CC((,, pdpd))1111Li Li reaction

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Current experimental situation: Current experimental situation: 112,132,13BeBe

Er, MeV Decay mode

10,212,815,5

α + 8He

13,514,5

6He + 6He

25,028,0

p + 11Li

Highly excited Highly excited states states of of 1122Be [1]Be [1]

Excited states of Excited states of 1133BeBe

Er, MeV or as, fm Г, MeV Work

-3,4 fm (g.s.) [2]0,51(1) 0,45(3) [2]

2,0 [3]2,39(5) 2,4(2) [2]

3,0 [3][1] R.J. Charity et al. // Phys. Rev. C 76 (2007) 064313[2] Y. Kondo et al. // Phys. Lett. B 360 (2010) 245[3] H. Simon et al. // Nucl. Phys. A 791 (2007) 267

Highly excited states of Highly excited states of 12,1312,13BeBe

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1414C(C(,p),p)1313BeBe 1414C(C(,d),d)1212BeBe

MM spectrum for the 1414C(C(,p),p)1313BeBe reaction

MM spectrum for the 1414C(C(,d),d)1212BeBereaction

π¯ + 14C → p + 13Be* d + 11Li

π¯ + 14C → d + 12Be* p + 11Li

Er ≈ 30 MeV

CONCLUSIONSCONCLUSIONS

Search for the rare cluster structure of the 1414CC isotope was studied in -

absorption reaction 1144CC((,, pd)X pd)X;;

The evidence of the rare cluster structure of the 1414C (C (33p + p + 1111Li) Li) was found

for the first time;

Indications on highly excited states of 12,13Be were found with the energy

EErr ≈ 30 MeV ≈ 30 MeV, which decay onto 12Be → p + 11Li and 13Be → d + 11Li;

Ground state and 3 excited states of 11Li were found. The most excited

level with the energy EErr = = 3.9 ± 0.33.9 ± 0.3 MeV MeV was found for the first time

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Thank you Thank you for your for your attention!attention!

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