Large hadron collider constraints on some simple $$Z^\prime $$ models for $$b\rightarrow s \mu ^+\mu ^-$$ anomalies

We examine current Large Hadron Collider constraints on some simple $$Z^\prime $$ Z ′ models that significantly improve on Standard Model fits to $$b\rightarrow s \mu ^+\mu ^-$$ b → s μ + μ - transition data. The models that we consider are the ‘third family baryon number minus second family lepton number’ ($${B_3-L_2}$$ B 3 - L 2 ) model and the ‘third family hypercharge’ model and variants. The constraints are applied on parameter regions of each model that fit the $$b\rightarrow s \mu ^+\mu ^-$$ b → s μ + μ - transition data and come from high-mass Drell–Yan di-muons and measurements of Standard Model processes. This latter set of observables place particularly strong bounds upon the parameter space of the $${B_3-L_2}$$ B 3 - L 2 model when the mass of the $$Z^\prime $$ Z ′ boson is less than 300 GeV.

Nonperturbative effects in the Standard Model with gauged 1-form symmetry

We study the Standard Model with gauged $$ {\mathrm{\mathbb{Z}}}_{N=2,3,6}^{(1)} $$ ℤ N = 2 , 3 , 6 1 subgroups of its $$ {\mathrm{\mathbb{Z}}}_6^{(1)} $$ ℤ 6 1 1-form global symmetry, making the gauge group $$ \frac{\mathrm{SU}(3)\times \mathrm{SU}(2)\times \mathrm{U}(1)}{{\mathrm{\mathbb{Z}}}_N} $$ SU 3 × SU 2 × U 1 ℤ N . We show that, on a finite $$ {\mathbbm{T}}^3 $$ T 3 , there are self-dual instantons of fractional topological charge. They mediate baryon- and lepton-number violating processes. We compare their amplitudes to the ones due to the usual BPST-instantons. We find that the small hypercharge coupling suppresses the fractional-instanton contribution, unless the torus size is taken sub-Planckian, or extra matter is added above the weak scale. We also discuss these results in light of the cosmological bounds on the torus size.

A Covariant Cauchy-Schwartz Measure’s Bounding Conditions to BSM Searches

Solving for the missing masses in the Higgs resonances, it was necessary to extend, even quantitatively via an index measurable amount, the SM using a threshold related longitudinal violation procedure. The obtained expression, by being non-contributing via its non-anomalously resulting parameter, is linked to a Cauchy-Schwartz 4-scalar product ratio type of two virtual Gauge Bosons momenta in its minimal anomalous configuration, as vs. its non-anomalous internal. Changing the bounds from energy into momenta, a convexity condition appears. Such technique clarifies the perturbative e.m. fields’ extensions into perturbative and non-perturbative QCD.In applications, there is the violation of the chiral insertion by the axion into neutrinos, and the Lepton number when passing form velocity to spin resonances, such confirming the CS procedure as plus the defiance of the SM comes through their branching ratios but not their angular distributions. Further which if remaining at the same level of minimization can restore the universality of extendibility in the Higgs self-couplings.Leading into deriving the phase of K0 → π+π-, in A(∆1=2)/A(∆1=0) so a conformal skipping dynamical shift from direct CP violation of D0 → K+K- and D0 → π+π- asymmetries, in the long-short mixing concords the phase of KL → π0ννbar, solving the KOTO anomaly.

Operator bases in effective field theories with sterile neutrinos: d ≤ 9

We obtain the complete and independent bases of effective operators at mass dimension 5, 6, 7, 8, 9 in both standard model effective field theory with light sterile right-handed neutrinos (νSMEFT) and low energy effective field theory with light sterile neutrinos (νLEFT). These theories provide systematical parametrizations on all possible Lorentz-invariant physical effects involving in the Majorana/Dirac neutrinos, with/without the lepton number violations. In the νSMEFT, we find that there are 2 (18), 29 (1614), 80 (4206), 323 (20400), 1358 (243944) independent operators with sterile neutrinos included at the dimension 5, 6, 7, 8, 9 for one (three) generation of fermions, while 24, 5223, 3966, 25425, 789426 independent operators in the νLEFT for two generations of up-type quarks and three generations of all other fermions.

On the role of leptonic CPV phases in cLFV observables

In extensions of the standard model by Majorana fermions, the presence of additional CP violating phases has been shown to play a crucial role in lepton number violating processes. In this work we show that (Dirac and Majorana) CP violating phases can also lead to important effects in charged lepton flavour violating (cLFV) transitions and decays, in some cases with a significant impact for the predicted rates of cLFV observables. We conduct a thorough exploration of these effects in several cLFV observables, and discuss the implications for future observation. We emphasise how the presence of leptonic CP violating phases might lead to modified cLFV rates, and to a possible loss of correlation between cLFV observables.

Inverse Seesaw, dark matter and the Hubble tension

We consider the inverse Seesaw scenario for neutrino masses with the approximate Lepton number symmetry broken dynamically by a scalar with Lepton number two. We show that the Majoron associated to the spontaneous symmetry breaking can alleviate the Hubble tension through its contribution to $$\Delta N_\text {eff}$$ Δ N eff and late decays to neutrinos. Among the additional fermionic states required for realizing the inverse Seesaw mechanism, sterile neutrinos at the keV-MeV scale can account for all the dark matter component of the Universe if produced via freeze-in from the decays of heavier degrees of freedom.

Muonium-Antimuonium Conversion

The MACS experiment performed at PSI in the 1990s provided an yet unchallenged upper bound on the probability for a spontaneous conversion of the muonium atom, { M=}({\mu^+e^-})M=(μ+e−), into its antiatom, antimuonium {\overline{{M}} = }({\mu^-e^+})M¯=(μ−e+). It comprises the culmination of a series of measurements at various accelerator laboratories worldwide. The experimental limits on the process have provided input and steering for the further development of a variety of theoretical models beyond the standard theory, in particular for models which address lepton number violating processes and matter-antimatter oscillations. Several models beyond the standard theory could be strongly disfavored. There is interest in a new measurement and improved sensitivity could be reached by exploiting the time evolution of the conversion process, e.g., at intense pulsed muonium sources.