Related papers: Spin-$1/2$ invisible particles in heavy meson deca…
Very recently, the LHCb collaboration has observed in the final state $\Lambda_c^+ K^-\pi^+\pi^+$ a resonant structure that is identified as the doubly-charmed baryon $\Xi_{cc}^{++}$. Inspired by this observation, we investigate the weak…
The NA62 experiment at the CERN SPS reports a study of a sample of $4 \times10^{9}$ tagged $\pi^0$ mesons from $K^+ \to \pi^+ \pi^0 (\gamma)$, searching for the decay of the $\pi^0$ to invisible particles. No signal is observed in excess of…
Neutral fermions of spin $\frac 12$ with magnetic moment can interact with electromagnetic fields through nonminimal coupling. The Dirac--Pauli equation for such a fermion coupled to a spherically symmetric or central electric field can be…
Motivated by the large rates of $B\rightarrow (\chi_{c0}, \chi_{c2}, h_c)K$ decays observed by the $BABAR$ and Belle collaborations, we investigate the nonfactorizable contributions to these factorization-forbidden decays, which can occur…
The transition form factors for doubly heavy baryons into a spin-$1/2$ or spin-$3/2$ ground-state baryon induced by both the charged current and the flavor changing neutral current are systematically studied within the light-front quark…
With updated experimental data and improved theoretical calculations, several significant deviations are being observed between the Standard Model predictions and the experimental measurements of the branching ratios of $\bar{B}_{(s)}^0\to…
We consider the quark-meson model with two quark flavors in a constant external magnetic field $B$ at finite temperature $T$ and finite baryon chemical potential $\mu_B$. We calculate the full renormalized effective potential to one-loop…
We study SU(2) lattice gauge theory with two flavors of Wilson fermion at non-zero chemical potential mu and low temperature on a 8^3x16 system. We identify three regimes along the mu-axis. For mu<~m_pi/2 the system remains in the vacuum…
Spin dependent fragmentation functions for heavy flavor quarks to fragment into heavy baryons are calculated in a quark-diquark model. The production of intermediate spin 1/2 and 3/2 excited states is explicity included. $\Lambda_b$ ,…
We present measurements of the branching fractions and a search for CP-violating charge asymmetries in charmless hadronic decays of B mesons into two-body final states of kaons and pions. The results are based on a data sample of…
A search for a massless beyond-standard-model particle is performed in the decay $\Xi^{0}\to\Lambda+\text{invisible}$ using $(1.0087 \pm 0.0044)\times 10^{10}$ $J/\psi$ events collected with the BESIII detector at the BEPCII collider. No…
The most general Lagrangian consistent with chiral, heavy quark, and strong interaction symmetries to order $1/M$ and to linear order in the SU(3) vector and axial currents is presented. Two new dimensionful and five dimensionless couplings…
The NA62 experiment at CERN reports searches for $K^+\to\mu^+N$ and $K^+\to\mu^+\nu X$ decays, where $N$ and $X$ are massive invisible particles, using the 2016-2018 data set. The $N$ particle is assumed to be a heavy neutral lepton, and…
The weak decays of a spin-$1/2$ doubly charm baryon (${\cal B}_{cc}$) to a spin-$1/2$ singly charm baryon (${\cal B}_c$) and a light vector meson ($V$) are studied under a phenomenological scheme. The contributions are classified into…
We evaluate semileptonic decays of spin-1/2 and spin-3/2 doubly heavy $cb$ baryons. The decays are driven by a $c\to s,d$ transition at the quark level. We check our results for the form factors against heavy quark spin symmetry constraints…
A search for a long-lived scalar particle $\chi$ is performed, looking for the decay ${B^+ \to K^+ \chi}$ with ${\chi \to \mu^+\mu^-}$ in $pp$ collision data corresponding to an integrated luminosity of $3\, {\rm fb}^{-1}$, collected by the…
If new particles are discovered at the LHC, it will be important to determine their spins in as model-independent a way as possible. We consider the case, commonly encountered in models of physics beyond the Standard Model, of a new scalar…
New light pseudoscalars, such as axion-like particles, appear in many well-motivated extensions of the Standard Model and provide an exciting target for present and future experiments. We study the experimental sensitivity for such…
In the covariant light-front quark model, we investigate the $B_c\to h_c, \chi_{c0,1,2}$ form factors. The form factors are evaluated in space-like kinematic region and are recasted to the physical region by adopting the exponential…
We explore the strangeness-changing decays of the lightest hyperons into another baryon plus missing energy within and beyond the standard model (SM). In the SM these processes arise from the loop-induced quark transition $s\to d\nu\bar\nu$…