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SUMMARY:Search for halo in isobar-analog states
DTSTART;VALUE=DATE-TIME:20201008T090000Z
DTEND;VALUE=DATE-TIME:20201008T091500Z
DTSTAMP;VALUE=DATE-TIME:20260515T130907Z
UID:indico-contribution-2271@cern.ch
DESCRIPTION:Speakers: Alla Demyanova ()\nOne of the most striking discover
 ies in nuclear physics made at the end of the past century was the finding
  the neutron halo in the ground states of some light nuclei located near t
 he neutron stability boundary. The halo manifests itself in the presence o
 f a diffuse surface region surrounding a core with a normal nuclear densit
 y and containing only neutrons. The result is a long "tail" of their wave 
 function and\, correspondingly\, an increase in the radius of the entire n
 ucleus in a given state.\n\nThe discovery of the halo led to a revision of
  many existing ideas in nuclear physics. The purpose of our research is to
  search and study halo in isobar - analog states of light nuclei. The stud
 y of states with a halo in isobar analogs allows one to investigate the ma
 nifestation of isotopic invariance at new objects and to relate the proper
 ties of the neutron and proton halo. Of particular interest is the accumul
 ation of information that states possessing halo properties can be located
  not only in the discrete spectrum\, but also in the continuum\, and the p
 roblem of their unified description is formulated as one of the most impor
 tant The question of the existence of halo in isobar - analog states has s
 o far not been practically raised in the experimental plan.\nOur approach 
 is based on measuring the radii of states in which the halo exists or can 
 exist. Its first application made it possible to determine the proton halo
  in an unbound state of $^{13}$N. \n\nThe first object we started was the 
 triplet A=12. Radii of the states of the isobaric triplet $^{12}$B-$^{12}$
 C-$^{12}$N were determined using two methods asymptotic normalization coef
 ficients (ANC) and modified diffraction method (MDM). We obtained that the
  1- excited states at E$_x$ = 2.62\, 17.23\, and 1.80 MeV\, respectively\,
  possess one-nucleon (neutron or proton) halo structure. The enlarged radi
 i and large values of D$_1$ coefficient are also found for the 2$^-$ state
 s of $^{12}$B\, $^{12}$C\, and $^{12}$N at E$_x$ = 1.67\, 16.57 and 1.19 M
 eV\, respectively. These IASs also can be regarded as candidates to the st
 ates with one-nucleon (neutron or proton) halo.\n\nThe second object was t
 riplet A=14. Signs of neutron halo in the 1$^{-}$ (6.09 MeV) state of $^{1
 4}$C have been revealed earlier by two independent groups. We confirmed th
 is result independently and studied isobaric analog 1$^{-}$ states of neig
 hboring $^{14}$N and $^{14}$O nuclei. The differential cross sections of t
 he $^{14}$C($\\alpha$\,$\\alpha$)$^{14}$C$^*$ (6.09 MeV\, 1$^{-}$)  inelas
 tic scattering\, the $^{13}$C($^{3}$He\,d)$^{14}$N$^*$ (8.06 MeV\, 1$^{-}$
 )\, and the $^{14}$N($^{3}$He\,t)$^{14}$O$^*$ (5.17 MeV\, 1$^{-}$) reactio
 ns are analyzed by the MDM and ANC. The rms radii for all three mirror nuc
 lei in the studied 1$^-$ states are found almost the same. The signs of pr
 oton halo in the 1$^-$ state of $^{14}$N are identified for the first time
 .\n\nOur future plans are connected with the radii of states of the $^6$Li
  and $^6$Be nuclei members of the $^6$He-$^6$Li-$^6$Be isobaric triplet. T
 he formation of a neutron-proton halo in the $^6$Li state (3.56 MeV\, 0$^+
 $) was predicted. The theory admits the existence in this state of the so-
 called "tango structure". A proton or two-proton halo is expected in the g
 round state of $^6$Be. The radii of the above states will be determined by
  inelastic scattering and the ($^3$He\,t) reaction using MDM.\n\nhttps://i
 ndico.particle.mephi.ru/event/35/contributions/2271/
LOCATION:Zoom Nuclear
URL:https://indico.particle.mephi.ru/event/35/contributions/2271/
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