The Impurity Components in the 7Be Solar Neutrino Flux

Oct 12, 2020, 6:40 PM


Oral report Section 5. Neutrino physics and astrophysics. Section 5. Neutrino physics and astrophysics


Юрий Романов Ю.И.


The Impurity Components in the 7Be Solar
Neutrino Flux
Romanov Yu.I.
Kosygin Russian State University, Moscow, Russia

In the present work, a development [1], the flavor structure of the 7Be
solar neutrino (SN) flux is investigated.
The electron spectrum of the (v_e ) ̅e-scattering differs from the fairly flat
spectra of all neutrinos. Such difference will open the way for the Borexino
Collaboration to search for an antineutrino admixture in the SN flux [2].
If the part of this flux transforms into neutrinos of the second and third
generations and related antiparticles v ̅e, the total electroweak spectrum of recoil electrons can be written in the form:

(dσ/dT)tot= P(v_e ) (dσ(vee))/dT +P_(v_(μ,τ) ) (dσ(v_(μ,τ) e))/dT +P_(¯v_e ) (dσ( v ̅ee))/dT , (1)

where T is the kinetic energy of the final electron.
The table
P_(¯v_e ) (dσ/dT)tot
0 [0.28; 0.36]
0.05 [0.27; 0.39]
0.1 [0.27; 0.41]
0.2 [0.26; 0.46]
0.3 [0.25; 0.51]
shows the results of calculations based on the Borexino data: a limit of the conversion probability P
(v_e→v ̅e ) < 0.35 (90% C.L.) for 862 keV 7Be neutrinos [2], under the assumption of v_e transition to other active neutrino flavors, the SN survival probability P(v_e )= 0.51 ± 0.07 [3].
Each spectrum is presented by ten values of the differential cross sections, corresponding to the recoil electron kinetic energy for the kinematically allowed escape angles, determined by the segment [0°; 90°].
The graphical image of these spectra is presented in the form of figures.

  1. Yu.I. Romanov // Bull.RAS. Phys. 2015. V. 79. P. 945.
  2. G. Bellini et al. (Borexino Collaboration) // Phys. Lett. B. 2011. V.696. P.191.
  3. G. Bellini et al. (Borexino Collaboration) // Phys. Rev. Lett. 2011. V.107. P.141302.

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