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R. Ferrandes

Publications and source records attributed to R. Ferrandes.

13 recordsLinked to original sources
arXiv2008

FCNC $B_s$ and $Λ_b$ transitions: Standard Model versus a single Universal Extra Dimension scenario

We study the FCNC $B_s \to ϕγ, ϕν\bar ν$ and $Λ_b \to Λγ, Λν\bar ν$ transitions in the Standard Model and in a scenario with a single Universal Extra Dimension. In particular, we focus on the present knowledge of the hadronic uncertainties and on possible improvements. We discuss how the measurements of these modes can be used to constrain the new parameter involved in the extra dimensional scenario, the radius $R$ of the extra dimension, completing the information available from B-factories. The rates of these $b \to s$ induced decays are within the reach of new experiments, such as LHCb.

hep-ph↗
arXiv2008

B, D and K decays

With the advent of the LHC, we will be able to probe New Physics (NP) up to energy scales almost one order of magnitude larger than it has been possible with present accelerator facilities. While direct detection of new particles will be the main avenue to establish the presence of NP at the LHC, indirect searches will provide precious complementary information, since most probably it will not be possible to measure the full spectrum of new particles and their couplings through direct production. In particular, precision measurements and computations in the realm of flavour physics are expected to play a key role in constraining the unknown parameters of the Lagrangian of any NP model emerging from direct searches at the LHC. The aim of Working Group 2 was twofold: on one hand, to provide a coherent, up-to-date picture of the status of flavour physics before the start of the LHC; on the other hand, to initiate activities on the path towards integrating information on NP from high-pT and flavour data.

hep-ph↗
arXiv2007

Puzzles in charm spectroscopy

We briefly analyze aspects of open and hidden charm resonances, discussing in particular the mesons $D_{sJ}(2860)$ and X(3872).

hep-ph↗
arXiv2006

Spin effects in rare $B \to X_s τ^+ τ^-$ and $B \to K^{(*)} τ^+ τ^-$ decays in a single Universal Extra Dimension scenario

We study the branching fractions and the lepton polarization asymmetries of rare $B \to X_s τ^+ τ^-$ and $B \to K^{(*)} τ^+ τ^-$ modes within the Standard Model and in the Appelquist-Cheng-Dobrescu model, which is a New Physics scenario with a single universal extra dimension. In particular, we investigate the sensitivity of the observables to the radius $R$ of the compactified extra-dimension, which is the only new parameter in this New Physics model. For the exclusive transitions we study the uncertainties due to the hadronic matrix elements using two set of form factors, finding that in many cases such uncertainties are small. In particular, we show that the $τ^-$ polarization asymmetries become free of hadronic uncertainties if Large Energy relations for the form factors, valid for low momentum transfer to the lepton pair, are used. We also consider $K^*$ helicity fractions and their sensitivity to the compactification parameter.

hep-ph↗
arXiv2006

New open and hidden charm spectroscopy

Many new results on open and hidden charm spectroscopy have been obtained recently. We present a short review of the experimental findings in the meson sector, of the theoretical interpretations and of the open problems, with a discussion on the possibility that some mesons are not quark-antiquark states.

hep-ph↗
arXiv2006

Aspects of non leptonic $B_s$ decays

I discuss a model independent determination of the widths of a class of two-body $\bar{B}_s^0 $ decays induced by $b \to c \bar u d$ and $b \to c \bar u s$ transitions. The analysis is based on $SU(3)_F$ symmetry and exploits existing information on $\bar B \to D_{(s)} P$ and $\bar B \to D_{(s)} V$ decays, with $P$ and $V$ a light pseudoscalar or vector meson. The results are relevant for the $B_s$ physics programmes at the hadron colliders and at the $e^+ e^-$ factories running at the peak of $Υ(5S)$.

hep-ph↗
arXiv2006

Exclusive $B \to K^{(*)} \ell^+ \ell^-$, $B \to K^{(*)} ν{\bar ν}$ and $B \to K^* γ$ transitions in a scenario with a single Universal Extra Dimension

We analyze the exclusive rare $B \to K^{(*)} \ell^+ \ell^-$, $B \to K^{(*)} ν\bar ν$ and $B \to K^* γ$ decays in the Applequist-Cheng-Dobrescu model, which is an extension of the Standard Model in presence of universal extra dimensions. In particular, we consider the case of a single universal extra dimension. We study how spectra, branching fractions and asymmetries depend on the compactification parameter 1/R, and whether the hadronic uncertainty due to the form factors obscures or not such a dependence. We find that, using present data, it is possible in many cases to put a sensible lower bound to 1/R, the most stringent one coming from $B \to K^* γ$. We also study how improved experimental data can be used to establish stronger constraints to this model.

hep-ph↗
arXiv2006

Model independent analysis of a class of $\bar{B}_s^0 $ decay modes

The widths of a class of two-body $\bar{B}_s^0 $ decays induced by $b \to c \bar u d$ and $b \to c \bar u s$ transitions are determined in a model-independent way, using $SU(3)_F$ symmetry and existing information on $\bar B \to D_{(s)} P$ and $\bar B \to D_{(s)} V$ decays, with $P$ and $V$ a light pseudoscalar or vector meson. The results are relevant for the $B_s$ physics programmes at the hadron colliders and at the $e^+ e^-$ factories running at the peak of $Υ(5S)$.

hep-ph↗
arXiv2005

On the structure of $D_{sJ}^*(2317)$ and $D_{sJ}(2460)$

We discuss the structure of the narrow mesons with charm and strangeness $D_{sJ}^*(2317)$ and $D_{sJ}(2460)$, stressing the role of the radiative decay modes in shedding light on the quark content of these states. We argue that present experimental data favour the interpretation of the two states as ordinary $\bar c s$ mesons. We suggest the existence of resonances with similar properties and well predicted masses in the $\bar b s$ sector.

hep-ph↗
arXiv2004

Interpretation of D$_{sJ}^*$(2317) and D$_{sJ}$(2460)

The experimental status of the recently observed resonances which could be interpreted as c$\bar q$ mesons with s$_l^P={1/2}^+$ is reviewed. In the framework of HQET and chiral perturbation theory, strong and radiative widths of these states are computed in the hypothesis that they are c$\bar q$ states, obtaining results consistent with the experimental measurements. Masses and widths for the analogous states containing a beauty quark are also predicted.

hep-ph↗
arXiv2004

Excited Charmed Mesons: Observations, Analyses and Puzzles

We review the status of recently observed positive parity charmed resonances, both in the non-strange and in the strange sector. We describe the experimental findings, the main theoretical analyses and the open problems deserving further investigations.

hep-ph↗