On the recently observed tensions in B decays

In the LHC era, the discovery of New Physics signals is the major ambition of the high-energy physics community and flavor physics can provide access to new heavy particles (Kaluza-Klein modes, supersymmetric particles . . . ) in complementary way with respect to direct searches. Signals of possible deviations with respect to the Standard Model have been recently claimed both by BABAR and LHCb through the analyses of specific semileptonic B-meson decays. First, I’ll focus on semileptonic b → c decay with a τ lepton in the final states for which new BABAR measurements are available, showing a deviation from the Standard Model at 3.4 σ level. I study the effects of a new tensor operator in the effective weak Hamiltonian on a set of observables, in semileptonic B → D(∗) modes as well as in semileptonic B and Bs decays to excited charmed mesons. Moreover, I discuss the phenomenology of the mode B → K∗� +� −, in the framework of a warped extradimensional model. Since a complete set of form factor independent observables have been recently measured by the LHCb Collaboration, with few sizable deviations with respect to the Standard Model in some of them, it would be interesting to put constraints on such a scenario from the FCNC transition b → s�+�−

On the recent anomalies in semileptonic B decays

Both BABAR and LHCb Collaborations have recently claimed signals of pos- sible deviations with respect to the Standard Model through the analyses of specific semileptonic B-meson decays. We firstly investigate the semileptonic b → c decay with a τ lepton in the final state for which new BABAR measurements are available, showing a deviation from the Standard Model at 3.4 σ level. We study the effects of a new ten- sor operator in the effective weak Hamiltonian on a set of observables, in semileptonic B → D (∗) modes as well as in semileptonic B and Bs decays to excited charmed mesons. Moreover, we discuss the phenomenology of the mode B → K ∗ � + � − , in the framework of a warped extra-dimensional model. Since a complete set of form factor almost in- dependent observables have been recently measured by the LHCb Collaboration, with few sizable deviations with respect to the Standard Model in some of them, it would be interesting to put constraints on such a scenario from the FCNC transition b → s� + � − . 1 Semileptonic B-meson decays with a τ lepton in the final state

On the anomalies recently discovered in semileptonic B decays to the third family

The ratios R(D-(*)) = B(B -> D-(*) t (nu) over bar (tau))/B(B -> D-(*) mu(nu) over bar (mu)) measured by BABAR Collaboration deviate from the standard model expectations; at the same time the purely leptonic channel B -> tau(nu) over bar (tau) has been found in better consistency with the standard model. We provide an attempt to reconcile these two experimental facts, within a New Physics Scenario, by adding a tensor operator in the effective weak Hamiltonian. We calculate the effects of such an operator in a set of observables, in semileptonic B -> D-(*) modes as well as in semileptonic B and B-s decays to excited positive parity charmed mesons

B→Kη(′)γB\to K \eta^{(\prime)} \gamma decays in the standard model and in scenarios with universal extra dimensions

We study the radiative $B \to K \eta^{(\prime)} \gamma$ decays, which are important to investigate CP violation, and are also relevant to assess the role of the exclusive modes induced by the $b \to s \gamma$ transition to saturate the inclusive $B \to X_s \gamma$ decay rate. Moreover, these channels do not display the same hierarchy as $B \to K \eta^{(\prime)}$ modes, for which the decay into $\eta^\prime$ is enhanced with respect to one into $\eta$. The three-body radiative decays reverse the role: we find that this experimentally observed behavior (although affected by a large uncertainty in the case of the $\eta^\prime$) is reproduced in the theoretical analysis. We compute a $B^* \to K$ form factor, needed for this study, using light cone QCD sum rules, and discuss a relation expected to hold in the large energy limit for the light meson. Finally, we examine $B\to K \eta \gamma$ in two extensions of the standard model with universal extra dimensions, to investigate the sensitivity of this rare mode to such a kind of new physics effects.Comment: RevTeX, 17 pages, 7 figures. High resolution figures available upon request. Matches the published versio

Mechanical weed control strategies for grain amaranth (Amaranthus cruentus L.)

Received: January 25th, 2022 ; Accepted: April 5th, 2022 ; Published: April 19th, 2022 ; Correspondence: [email protected], no herbicide is registered for grain amaranth in Europe, the United States and South America. Hence, weed control must be addressed with alternative methods. Field trials were conducted in 2018 and 2019 in Central Italy by comparing some mechanical weed control treatments in grain amaranth (Amaranthus cruentus L.). In 2018, the five treatments were: untreated control (T118), cutter hoeing (T218), flat share cuts and one central duck foot tine (T318), flat share cuts and two central duck foot tines (T418), and three duck foot tines (T518). In 2019, the five treatments were: untreated control (T119), three duck foot tines (T219), flex tine harrowing (T319), flex tine harrowing plus finger weeding with red fingers (T419), and finger weeding with red fingers (T520). In 2018, amaranth was a successful competitor against weeds from 40 days after emergence (10 true leaf stage, corresponding to BBCH code 15). The competitive ability was showed by excellent seed yields averaging 1.2 t ha-1 , for all treatments. This feature was also confirmed to some degree in 2019. However, seed yield in 2019 was more strongly influenced by treatment as well as by the lower emergence of plants. All the mechanical methods employed can be effectively used for weed control in grain amaranth. Treatments with the flex tine harrower and finger weeder negatively affected the plant density at harvest, necessitating further optimization. However, combined mechanical strategies proved the most effective, especially in controlling dicot weeds. There is a need to optimize strategies, with mechanical equipment, to anticipate and improve the ground cover of amaranth. These strategies include selecting optimal plant density and the correct distancing between the rows for easier mechanical control

Quantum dynamics of a high-finesse optical cavity coupled with a thin semi-transparent membrane

We study the quantum dynamics of the cavity optomechanical system formed by a Fabry-Perot cavity with a thin vibrating membrane at its center. We first derive the general multimode Hamiltonian describing the radiation pressure interaction between the cavity modes and the vibrational modes of the membrane. We then restrict the analysis to the standard case of a single cavity mode interacting with a single mechanical resonator and we determine to what extent optical absorption by the membrane hinder reaching a quantum regime for the cavity-membrane system. We show that membrane absorption does not pose serious limitations and that one can simultaneously achieve ground state cooling of a vibrational mode of the membrane and stationary optomechanical entanglement with state-of-the-art apparatuses.Comment: 14 pages, 7 figure

Quantum dynamics of a vibrational mode of a membrane within an optical cavity

Optomechanical systems are a promising candidate for the implementation of quantum interfaces for storing and redistributing quantum information. Here we focus on the case of a high-finesse optical cavity with a thin vibrating semitransparent membrane in the middle. We show that robust and stationary optomechanical entanglement could be achieved in the system, even in the presence of nonnegligible optical absorption in the membrane. We also present some preliminary experimental data showing radiation-pressure induced optical bistability.Comment: 6 pages, 2 figures. Work presented at the conference QCMC 2010 held on 19-23 July 2010 at the University of Queensland, Brisbane, Australi

Exclusive b → s ν ν induced transitions in the RSc model

We study a set of exclusive B and Bs decay modes induced by the rare (Formula presented.) transition in the RSc model, an extra-dimensional extension of the standard model with warped 5D metric and extended gauge group. We discuss the role of correlations among the observables, and their importance for detecting the predicted small deviations from the standard model expectations

Exclusive b→sνν¯ induced transitions in the RS c model

We study a set of exclusive B and Bs decay modes induced by the rare b→sνν¯ transition in the RS c model, an extra-dimensional extension of the standard model with warped 5D metric and extended gauge group. We discuss the role of correlations among the observables, and their importance for detecting the predicted small deviations from the standard model expectations

Optomechanical sideband cooling of a thin membrane within a cavity

We present an experimental study of dynamical back-action cooling of the fundamental vibrational mode of a thin semitransparent membrane placed within a high-finesse optical cavity. We study how the radiation pressure interaction modifies the mechanical response of the vibrational mode, and the experimental results are in agreement with a Langevin equation description of the coupled dynamics. The experiments are carried out in the resolved sideband regime, and we have observed cooling by a factor 350 We have also observed the mechanical frequency shift associated with the quadratic term in the expansion of the cavity mode frequency versus the effective membrane position, which is typically negligible in other cavity optomechanical devices.Comment: 15 pages, 7 figure