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Clus e s a es in 11B
Danilo , A.N.; Demyano a, A.S.; Ogloblin, A.A.; Dmi ie , S.V.; Belyae a, T.L.;
Goncha o , S.A.; Gu o , Yu.B.; Maslo , V.A.; Sobole , Yu.G.; T zaska, Wladyslaw;
Khlebniko , S.V.; Bu ebae , N.; Zholdybaye , T.; Saduye , N.; Heikkinen, Pauli; Julin,
Rauno; Tyu in, G igo y
Danilo , A.N., Demyano a, A.S., Ogloblin, A.A., Dmi ie , S.V., Belyae a, T.L.,
Goncha o , S.A., Gu o , Yu.B., Maslo , V.A., Sobole , Yu.G., T zaska, W., Khlebniko ,
S.V., Bu ebae , N., Zholdybaye , T., Saduye , N., Heikkinen, P., Julin, R., & Tyu in, G.
(2014). Clus e s a es in 11B. In S. Luna di, P. Bizze i, S. Kabana, C. Bucci, M. Chia i, A.
Dainese, P. D. Nezza, R. Menegazzo, A. Nannini, & C. S. A. J. Valien e-Dobon (Eds.),
INPC 2013 – In e na ional Nuclea Physics Con e ence Fi enze, I aly, June 2-7, 2013
(A icle 03007). EDP Sciences. EPJ Web o Con e ences, 66.
h ps://doi.o g/10.1051/epjcon /20146603007
2014
Clus e s a es in 11B
A.N. Danilo 1a, A.S. Demyano a1, A.A. Ogloblin1, S.V. Dmi ie 1, T.L.Belyae a2, S.A.Goncha o 3,
Yu.B. Gu o 4, V.A. Maslo 5, Yu.G. Sobole 5, W. T zaska6, S.V. Khlebniko 7, N. Bu ebae 8, T.
Zholdybaye 8, N. Saduye 9, P. Heikkinen6, R. Julin6, G.P. Tyu in6
1 NRC Ku cha o Ins i u e, Moscow 123182, Russia
2 Uni e sidad Au onoma del Es ado de Mexico, Codigo Pos al 50000, Toluca, Mexico
3 Lomonoso Moscow S a e Uni e si y, Moscow, Russia
4 MEPhi, Moscow, Russia
5 JINR, Moscow egion, Russia
6 JYFL, Jy askyla, Finland
7 Khlopin Radium Ins i u e, S .-Pe e sbu g, Russia
8 Nuclea Physics Ins i u e, Alma y, Kazakhs an
9 Al-Fa abi Kazakh Na ional Uni e si y, Kazakhs an
Abs ac . The di e en ial c oss-sec ions o he elas ic and inelas ic 11B + α sca e ing
was measu ed a E(α) = 65 MeV. The analysis o he da a by Modi ied di ac ion model
(MDM) showed ha he RMS adii o he 11B s a e 3/2-, E* = 8.56 MeV is ~ 0.6 m la ge
han ha o he g ound s a e. The 12.56 MeV s a e was no obse ed con a y o he
p edic ions o he α-condensa e model. The 13.1 MeV s a e was exci ed wi h he angula
momen um ans e L = 4 con i ming i s belonging o he o a ional band wi h he 8.56
MeV s a e as a head.
1 In oduc ion
P og ess in he heo y o clus e physics, in pa icula , he hypo hesis abou possible exis ence o he
alpha-pa icle condensa e in nuclei ini ia ed wo k o ind nuclea s a es wi h ex emely la ge size. I
was p edic ed ha wo le els in 11B: ½-, E * = 8.56 MeV and ½+ (possibly a 12.56 MeV) ha e he
oo mean squa e adii R ms = 3.1 m [1] and ~ 6 m [2] co espondingly, while he g ound s a e has
R ms = 2.29 m.
Fo checking hese p edic ions di e en ial c oss sec ions o he inelas ic sca e ing α + 11B a E(α)
= 65 MeV we e measu ed and analyzed oge he wi h he da a ob ained a di e en ene gies. The
analysis was done by he Modi ied Di ac ion Model (MDM) [3]. This me hod allows de e mining
he adii R* ms o he exci ed s a es ia he di e ence o he di ac ion adii o he exci ed and he
g ound s a es using he exp ession:
R*= R0 + [R*
di − Rdi (0)] (1)
He e R0 is he RMS o he g ound s a e o he nucleus unde discussion, R*
di and Rdi (0) a e he
di ac ion adii de e mined om he posi ions o he minima and maxima o he expe imen al angula
dis ibu ions o he inelas ic and elas ic sca e ing co espondingly. Such app oach allowed inding he
a Co esponding au ho : danilo 1987@mail. u
DOI: 10.1051/
C
Owned by he au ho s, published by EDP Sciences, 2014
,
/
03007 (2014)
201
66
epjcon
EPJ Web o Con e ences
46603007
This is an Open Access a icle dis ibu ed unde he e ms o he C ea i e Commons A ibu ion License 2.0, which pe mi s
un es ic ed use, dis ibu ion, and ep oduc ion in any medium, p o ided he o iginal wo k is p ope ly ci ed.
A icle a ailable a h p://www.epj-con e ences.o g o h p://dx.doi.o g/10.1051/epjcon /20146603007
consis en alues o he RMS adius o he Hoyle s a e om 2H, 3He, 4He, 6Li, 12C inelas ic sca e ing
measu ed on he 12C a ge in a wide ene gy ange [4]. The goal o he expe imen was o de e mine
he adii alues o he exci ing s a es in 11B using MDM.
2 Expe imen al da a
We measu ed he di e en ial c oss-sec ions o he inelas ic α + 11B sca e ing wi h exci a ion he s a es
o 11B up o E* ~ 14 MeV. The expe imen was done a he JYFL cyclo on K130, Jy askyla
Uni e si y, Finland using LSC (La ge Sca e ing Chambe ) wi h ΔE-E elescopes o semiconduc o
coun e s. The a ge was an 11B sel -suppo ed ilm o 0.275 mb/cm2 hickness. The only signi ican
impu i y was 12C. The beam monoch oma iza ion sys em was used allowing p o iding he o al ene gy
esolu ion o he expe imen o be 150 keV.
A sample spec um is shown on Fig. 1.
40 45 50
0
80
160
240
11.6
coun s
E (MeV)
g.s.12C
4.4412C
2.12
4.44
5.02
6.74
7.29
7.98
8.56
9.27
10,34
10.6
11.27
12.6
12.92
13.1 g.s.
Figu e 1. A sample α-pa icles spec um a E (α) =65 MeV, Θ=53.5 deg.
3 Resul s and discussions
3.1 8.56 MeV s a e
The alue o he 8.56MeV s a e adius was de e mined o be R ms = 2.87 ± 0.12 m, which is 0.6 m
la ge han he adius o he g ound s a e being in ag eemen wi h he p e ious da a (R ms = 2.99 ± 0.18
m om Re . [5]).
The ob ained adius is p ac ically equal o he adius o he second exci ed s a e o 12C, he Hoyle
s a e. The adius o he Hoyle s a e was de e mined o be R ms = 2.89 ± 0.04 m [3].
So he ob ained esul oge he wi h he simila i y o he shapes o he angula dis ibu ions (Fig. 2)
and he simila i y o he ene gy dependence o di ac ion adii (Fig. 3) clea ly indica es o he
simila i y o he s uc u es o he 8.56 MeV s a e o 11B and he Hoyle s a e o 12C. The 8.56 MeV
s a e can be conside ed as an analogue o he Hoyle s a e in neighbo ing nuclei.
EPJ Web o Con e ences
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0 10 20 30 40 50 60 70 80 90
0,01
0,1
1
10
d/dΩ (mb/s )
CM
Figu e 2. Di e en ial c oss-sec ions o inelas ic
sca e ing α + 11B a Eα=65 MeV leading o 8.56
MeV s a e ( ed poin s) and inelas ic sca e ing α +
12C a Eα=65 MeV leading o 7.65 MeV s a e (black
poin s)
0 100 200 300
4,0
4,5
5,0
5,5
6,0
6,5
Rdi ( m)
Ec.m.(MeV)
Figu e 3. Ene gy dependence o di ac ion adii:
black dashed line – di ac ion adii o elas ic
sca e ing α + 12C, ed dashed line – o 7.65 Hoyle
s a e, black poin s – o elas ic α + 11B, black solid
line – linea i o black poin s, ed poin s – o
8.56 MeV s a e, ed solid line – linea i o ed
poin s
3.2 Ro a ional band based on 8.56 MeV s a e
We go p elimina y esul s o he di e en ial c oss-sec ion o he inelas ic sca e ing leading o 10.34
MeV (5/2-) and 13.1 MeV (9/2-) s a es. These s a es a e p edic ed [6,7] as he second and he ou h
membe s o he o a ional band based on he 8.56 MeV s a e. The beha io o he angula dis ibu ion
o he inelas ic sca e ing wi h he exci a ion o he 13.1 MeV s a e is he same as o he inelas ic
sca e ing o α + 12C wi h he exci a ion o he 14.08 MeV (Fig. 4). The las is well known o be
exci ed by ansi ion L=4. The MDM was used o es ima ing he adius o he 13.1 MeV s a e. The
bes i was ob ained wi h he di ac ion adius Rdi =4.5 m, he alue which coincides wi h ha o he
L = 4 ansi ion in he 12C (α, α’) eac ion o a new s a e o 12C a E* = 13.75 MeV [8] belonging o he
o a ional band based on he Hoyle s a e. In some a icles [6] he e a e assump ions ha he 13.1 MeV
s a e is he membe o he hypo he ical o a ional band based on he g ound s a e. Wi hin hese
assump ions he p e ious membe o his band is he 6.74 MeV s a e wi h abno mally la ge ine ia
momen um. We ha e go he angula dis ibu ion wi h he exci a ion o his s a e and didn’ obse e
any RMS adius enla gemen , wha is na u ally can be expec ed in acco dance wi h sha p inc ease o
ine ia momen um. I is qui e possible ha abo emen ioned o a ional band doesn’ exis and low-
lying s a es o 11B ha e no mal shell-model s uc u e. So he 13.1 MeV is mo e p obable o be he
membe o he band based on he 8.56 MeV s a e.
INPC 2013
03007-p.3
0 20 40 60 80
0,01
0,1
1
10
d

/dΩ (mb/s )
CM
Figu e 4. Di e en ial c oss-sec ions o inelas ic
sca e ing α + 11B a Eα = 65 MeV leading o 13.1
MeV s a e ( ed poin s) and inelas ic sca e ing α +
12C a Eα = 65 MeV leading o 14.08 MeV s a e
(black poin s)
3.3 12.56 MeV s a e
Fo he 12.56 MeV (½+, T=3/2) s a e [9] o 11B he e exis s con adic o y in o ma ion conce ning i s
isospin. The model [2] sugges ha Jπ=½+, T = ½.
In ou expe imen we obse ed a g oup o s a es, among hem is he s a e wi h exci a ion ene gy
12.6 MeV. Also such s a e was de ec ed in he esonance eac ion 7Li + α [6]. A T = 3/2 s a e is
unexpec ed o be obse ed in he inelas ic alpha pa icle sca e ing, so isospin o his s a e is T = ½.
P elimina y analysis o angula dis ibu ion indica es o angula ans e ed momen um L=1, so
spin o his s a e is 3/2+, in ag eemen wi h [6]. Thus, we can conclude ha he p edic ions [2] we e
no con i med.
Theo e ical calcula ions a e in a p og ess.
The wo k was suppo ed by he G an o RFBR, No 12-02-000927-a.
Re e ences
1. Y. Kanada-En’yo, Phys. Re . C 75, 024302 (2007)
2. T. Yamada and Y. Funaki, Phys. Re . C 82, 064315 (2010)
3. A.N. Danilo e al., Phys.Re . C 80, 054603 (2009)
4. A.S. Demyano a e al., Nucl. Phys. A 805, 489 (2008) (P oceedings o he 23 d In e n. Nuclea
Physics Con e ence (INPC2007), Tokyo, Japan, 3-8 June, 2007
5. A.S.Demyano a e al., In . J. o Mode n Physics E 20, 915 (2011)
6. H. Yamaguchi e al., Phys. Re . C 83, 034306 (2011)
7. T. Saha a and Y. Kanada-En’yo, Phys. Re . C 85, 054320, (2012)
8. A.A. Ogloblin e al., P oceeding o his con . INPC2013, pos e numbe - NS 160
9. F. Ajzenbe g-Selo e, Nucl. Phys. A 506, 1 (1990)
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