Connecting b → s ℓ ℓ ¯ $$ b\to s\ell \overline{\ell} $$ anomalies to enhanced rare nonleptonic

Abstract

The present data on a number of observables in b → sµ + µ − processes manifest some tensions with the standard model (SM). Assuming that these anomalies have a new physics origin, we consider the possibility that a Z boson is responsible for them. We further assume that its interactions with quarks also affect rare nonleptonic decays of thē B 0 s meson which are purely isospin-violating and tend to be dominated by electroweakpenguin contributions, namelyB 0 s → (η, η , φ)(π 0 , ρ 0 ). Most of these decays are not yet observed, and their rates are expected to be relatively small in the SM. Taking into account constraints from various measurements, including the evidence forB 0 s → φρ 0 recently seen by LHCb, we find that the Z effects onB 0 s → (η, φ)π 0 can make their rates bigger than the SM predictions by up to an order of magnitude. ForB 0 s → η π 0 , (η, η )ρ 0 , the enhancement factors are at most a few. Since the Z contributions to the different channels depend on different combinations of its couplings, observations of more of these decays in future experiments, along with improved b → sµ + µ − data, will probe this Z scenario more thoroughly.

Minimal Z′ models for flavor anomalies

“…Even though the experimental results are not conclusive yet, the global ts improve for models where the new physics contributions to the Wilson coef cient C µ 9 decrease it by a quarter of the SM prediction [11]. Because the only lepton in the associated Wilson operator is the muon eld, one of the preferred theoretical frameworks to explain these anomalies are the non-universal models [12][13][14][15][16][17][18][19][20], for which the electroweak (EW) parameters and quantum numbers are family dependent. In general, non-universal models are restricted severely by avor changing neutral currents (FCNC); however, as it is well-known [21], we can get rid of these problems by guaranteeing that the gauge couplings of the new physics to the left-handed down-type quarks become identical (we do not know anything about the mixing of the right-handed quarks so that we can assume a diagonal matrix.…”

R(K(⁎)) from dark matter exchange

“…Although the significance in either observation K or K ( * ) is not high, model-independent fits to both data, and possibly including quantities more sensitive to hadronic physics, including B s → µ + µ − , B s → φµ + µ − and the angular observable P 5 , indicate a higher significance of ∼ 4σ [5][6][7][8][9] Ref. [10] shows that the best fits and significance do not change appreciably whether one includes the hadronically sensitive observables or not, and that it is possible to find a good fit to the data by including a single dimension-6 operator in the effective Hamiltonian, The new physics contribution (1) can be obtained from tree-level exchange of a heavy Z vector boson [11][12][13][14][15][16][17][18] or leptoquark [19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36], or through loop effects of new particles. In ref.…”