Related papers: Discovering True Muonium at LHCb

The rare electromagnetic $J/\psi \to \mu^+\mu^-\mu^+\mu^-$ decay is observed with a significance greatly exceeding the discovery threshold, using proton-proton collision data collected by the LHCb experiment during 2016-2018 at a…

Fundamental physics could be described as having a muon problem. Discrepancies between theory and experiment in a number of muonic measurements ($r_P$, $a_\mu$, $H\rightarrow\mu\tau$, $\mathcal{R}_K$, $\mathcal{R}_{D^*}$) have been observed…

Motivated by renewed evidence for new physics in $b \to s\ell\ell$ transitions in the form of LHCb's new measurements of theoretically clean lepton-universality ratios and the purely leptonic $B_s\to\mu^+\mu^-$ decay, we quantify the…

The rare semi-leptonic decays $B\to K^\ast \ell^+\ell^-$, with $\ell=e, \mu$, are highly sensitive to new physics (NP) due to their suppression in the Standard Model (SM). Current LHCb measurements in the muon channel exhibit a significant…

A search for the rare decays $B^0_s \to\mu^+\mu^-$ and $B^0 \to\mu^+\mu^-$ is performed at the LHCb experiment. The data analysed correspond to an integrated luminosity of 1 fb$^{-1}$ of $pp$ collisions at a centre-of-mass energy of 7 TeV…

The search for axion-like particles $X$ in muon decays is an excellent opportunity for the MEG II and Mu3e experiments to extend their horizons beyond $\mu^+ \to e^+ \gamma$ and $\mu^+ \to e^+ e^- e^+$. A suitable process for both…

The $B$-factories and Large Hadron Collider experiments have demonstrated the ability to observe and measure the properties of bottomonium mesons. In order to discover missing states it is useful to know their properties to develop a…

A search for long-lived heavy neutral leptons produced in B-meson decays and decaying to a $ \mu^\pm \pi^\mp$ final state is performed with data collected by the LHCb experiment in proton-proton collisions at a centre-of-mass energy of 13…

One of the fundamental predictions of the Standard Model is Lepton Flavour Universality. Any deviation from this prediction would indicate the existence of physics beyond the Standard Model. Recent LHCb measurements present a pattern of…

Mu3e is an experiment currently under construction at the Paul Scherrer Institute in Switzerland, designed to search for the Lepton Flavor Violating (LFV) decay $\mu^+ \rightarrow e^+e^-e^+$. In extensions of the Standard Model (SM) that…

The LHCb experiment, bolstered up by the 10^12 b-hadrons to be produced yearly in its interaction region, is an excellent place to study rare B decays. Flavor-changing neutral currents are forbidden at tree level in the Standard Model. They…

We study the sensitivity of displaced vertex searches for heavy neutrinos produced in W boson decays in the LHC detectors ATLAS, CMS and LHCb. We also propose a new search that uses the muon chambers to detect muons from heavy neutrino…

The rare decay B --> K* mu+ mu- is considered to be a golden channel for LHCb, as the polarization of the K* allows a precise angular reconstruction resulting in many observables that offer new important tests of the Standard Model and its…

A search for the non-resonant decays $B^0_s \rightarrow \mu^{+}\mu^{-}\mu^{+}\mu^{-}$ and $B^0 \rightarrow \mu^{+}\mu^{-}\mu^{+}\mu^{-}$ is presented. The measurement is performed using the full Run 1 data set collected in proton-proton…

We utilize the lepton number violation signal process $p\, e^- \to \tau^+ jjj$ to search for heavy Majorana neutrinos at future proton-electron colliders. The LHeC (FCC-eh) is considered to run with an electron beam energy of 60 GeV, a…

We investigate a possibility that the $\mu^-\to e^+$ conversion is discovered prior to the $\mu^-\to e^-$ conversion, and its implications to the new physics search. We focus on the specific model including the mixing of the $SU(2)_L$…

A search for the decay $B^0\to\phi\mu^+\mu^-$ is performed using proton-proton collisions at centre-of-mass energies of 7, 8, and 13 TeV collected by the LHCb experiment and corresponding to an integrated luminosity of 9 fb$^{-1}$. No…

Both e+e- and {\mu}+{\mu}- colliders have been proposed as possible candidates for a lepton collider to complement and extend the reach of the Large Hadron Collider (LHC) at CERN. The physics program that could be pursued by a new lepton…

Intriguing results for tests of the universality of electrons and muons through measurements of rates of $B\to K \ell^+ \ell^-$ and similar decays have been in the spotlight for years. The LHCb collaboration has recently reported new…

Upcoming fixed-target experiments designed to search for new sub-GeV forces will also have sensitivity to the never before observed True Muonium atom, a bound state of a muon and anti-muon. We describe the production and decay…