Exploring CP-violation, via heavy neutrino oscillations, in rare B meson decays at Belle II

Abstract

In this article we study the rare B-meson decay via two on-shell almost-degenerate Majorana Heavy Neutrinos, into two charged leptons and two pseudoscalar mesons ($$B^{\pm } \rightarrow D^0 \ell ^{\pm }_1 \ell ^{\pm }_2 \pi ^{\mp }$$ B ± → D 0 ℓ 1 ± ℓ 2 ± π ∓ ). We consider the scenario where the heavy neutrino masses are $$\sim 2$$ ∼ 2 GeV and the heavy-light mixing coefficients are $$|B_{\ell N}|^2 \sim 10^{-5}$$ | B ℓ N | 2 ∼ 10 - 5 , and evaluate the possibility to measure the CP-asymmetry at Belle II. We present some realistic conditions under which the asymmetry could be detected.

CP violation in rare lepton-number-violating W decays at the LHC

“…This is the same decay that appears with a virtual W in the decays of mesons and τ leptons, studied in refs. [12][13][14][15][16][17][18][19] and [20,21], respectively. In those papers, it was pointed out that the interference between the N 1 and N 2 contributions can lead to a CP-violating rate difference between process and anti-process.…”

“…One particularly intriguing aspect of this scenatio is that the nearly-degenerate neutrinos can have masses as small as O(GeV) [11]. The possibility that there can be CP-violating LNV processes involving these light sterile neutrinos has led some authors to examine ways to see such effects in the decays of mesons [12][13][14][15][16][17][18][19] and τ leptons [20,21]. Note that these JHEP04(2021)021 studies all use as motivation the neutrino minimal standard model (νMSM) [22][23][24][25], which combines the seesaw mechanism and leptogenesis, and even provides a candidate for dark matter.…”

“…The idea of refs. [12][13][14][15][16][17][18][19][20][21] is as follows. The seesaw mechanism yields heavy-light neutrino mixing, which generates a W --N coupling.…”

“…The seesaw mechanism yields heavy-light neutrino mixing, which generates a W --N coupling. This leads to decays such as [17]. CP violation occurs because there are two heavy neutrinos, N = N 1 or N 2 , and these are nearly degenerate in mass.…”

$Δ$L=2 hyperon decays induced by Majorana neutrinos and doubly-charged scalars

“…On the other hand, ∆L = 2 hyperon decays allow the possibility to study channels involving equal-sign muon and electrons in the final state that are not available in nuclear decays due to limited phase space. There is a large amount of studies related to ∆L = 2 processes in decays of tau leptons [9][10][11][12][13][14][15][16], pseudoscalar mesons [17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33], and Λ b baryons [34][35][36][37], mainly motivated by the resonant effect produced by an intermediate Majorana neutrino and their study in flavor-factories experiments; this new study is motivated by the large dataset of hyperons pairs produced in charmonium decays that has been and are expected to be accumulated in the BESIII experiment [38,39].…”