Searcharxiv⌕ Search

arXiv subjects

J. H. Munoz

Publications and source records attributed to J. H. Munoz.

15 recordsLinked to original sources
arXiv2013

Axial-vector mesons from $τ\to APν_τ$ decays

Axial-vector mesons $a_1(1260)$, $f_1(1285)$, $h_1(1170)$, $K_1(1270)$, and $K_1(1400)$ can be produced in semileptonic $τ\to A P ν_τ$ decays, where $P$ stands for the pseudoscalar mesons $π$ or $K$. We calculate the branching ratios based in a meson dominance model. The exclusive channels $τ^-\to a_1(1260)^-π^0ν$, $τ^-\to a_1(1260)^0π^-ν$, and $τ^-\to h_1(1170)π^-ν$ turn out to be of order ${\cal O}(10^{-3})$, the channel $τ^-\to f_1(1285)π^-ν$ of order ${\cal O}(10^{-4})$, and channels $τ^-\to K_1(1270)^-π^0ν$, $τ^-\to K_1(1270)^0π^-ν$, $τ^-\to K_1(1400)^-π^0ν$, and $τ^-\to K_1(1400)^0π^-ν$ of order ${\cal O}(10^{-6})$. These results indicate that the branching ratios could be measured in experiments.

hep-ph↗
arXiv2011

Production of radially excited charmonium mesons in two-body nonleptonic Bc decays

We have computed branching ratios of two-body nonleptonic B_c \to X_{c\bar{c}}M decays, where X_{c\bar{c}} is the radially excited charmonium η_c(2S) or ψ(2S) meson, and M is a pseudoscalar (P) or a vector (V) or an axial-vector (A(^3P_1)) meson. We have assumed factorization hypothesis and calculated the form factors in the nonrelativistic ISGW2 quark model. We have found that some of these decays have branching ratios of the order of 10^{-3} - 10^{-4}.

hep-ph↗
arXiv2011

Tensor mesons produced in tau lepton decays

Light tensor mesons (T = a_2, f_2 and K_2^*) can be produced in decays of tau leptons. In this paper we compute the branching ratios of tau --> T pi nu decays by assuming the dominance of intermediate virtual states to model the form factors involved in the relevant hadronic matrix element. The exclusive f_2(1270) pi^- decay mode turns out to have the largest branching ratio, of O(10^-4) . Our results indicate that the contributions of tensor meson intermediate states to the three-pseudoscalar channels of tau decays are rather small.

hep-ph↗
arXiv2009

Nonleptonic charmless two-body $B \to AT$ decays

In this work we have studied hadronic charmless two-body B decays involving p-wave mesons in final state. We have calculated branching ratios of $B\to AT$ decays (where $A$ and $T$ denotes a $^3P_1$ axial-vector and a tensor meson, respectively), using $B \to T$ form factors obtained in the covariant light-front (CLF) approach, and the full effective Hamiltonian. We have obtained that $\mathcal{B}(B^{0} \to a_{1}^{+}a_{2}^{-}) =42.47 \times10^{-6}$, $\mathcal{B}(B^{+} \to a_{1}^{+}a_{2}^{0}) = 22.71 \times10^{-6}$, $\mathcal{B}(B \to f_{1}K_{2}^{*}) = (2.8-4) \times 10^{-6}$ (with $f_{1}=, f_{1}(1285),f_{1}(1420)$) for $θ_{^{3}P_{1}} = 53.2^{\circ}$, $\mathcal{B}(B \to f_{1}(1420)K_{2}^{*}) = (5.91-6.42) \times 10^{-6}$ with $θ_{^{3}P_{1}} = 27.9^{\circ}$, $\mathcal{B}(B \to K_{1}a_{2})= (1.7 - 5.7) [1-9.3] \times10^{-6}$ for $θ_{K_{1}} = -37^{\circ} [-58^{\circ}]$ where $K_1 = K_1(1270), K_1(1400)$. It seems that these decays can be measured in experiments at $B$ factories. Additionally, we have found that $\mathcal{B}(B \to K_{1}(1270)a_{2})/\mathcal{B}(B \to K_{1}(1400)a_{2})$ and $\mathcal{B}(B \to f_1(1420)K_{2}^{*})/\mathcal{B}(B \to f_1(1285)K_{2}^{*})$ ratios could be useful to determine numerical values of mixing angles $θ_{K_{1}}$ and $θ_{^{3}P_{1}}$, respectively.

hep-ph↗
arXiv2009

Nonleptonic charmless two-body B decays involving tensor mesons in the covariant light-front approach

We reanalyzed nonleptonic charmless two-body B decays involving tensor mesons in final state motivated by the disagreement between current experimental information and theoretical predictions obtained in ISGW2 model for some $\mathcal{B}(B \to P(V)T)$ (where $P$, $V$ and $T$ denote a pseudoscalar, a vector and a tensor meson, respectively). We have calculated branching ratios of charmless $B \to PT$ and $B\to VT$ modes, using $B \to T$ form factors obtained in the covariant light-front (CLF) approach and the full effective Hamiltonian. We have considered the $η-η^{\prime}$ two-mixing angle formalism for $B \to η^{(\prime)}T$ channels, which increases branching ratios for these processes. Our predictions obtained in the CLF approach are, in general, greater than those computed in the framework of the ISGW2 model and more favorable with the available experimental data. Specifically, our results for exclusive channels $B \to ηK_{2}^{*}(1430)$ and $B \to ϕK_{2}^{*}(1430)$ are in agreement with recent experimental information.

hep-ph↗
arXiv2007

Nonleptonic two-body B-decays including axial-vector mesons in the final state

We present a systematic study of exclusive charmless nonleptonic two-body B decays including axial-vector mesons in the final state. We calculate branching ratios of B\to PA, VA and AA decays, where A, V and P denote an axial-vector, a vector and a pseudoscalar meson, respectively. We assume naive factorization hypothesis and use the improved version of the nonrelativistic ISGW quark model for form factors in B\to A transitions. We include contributions that arise from the effective ΔB=1 weak Hamiltonian H_{eff}. The respective factorized amplitude of these decays are explicitly showed and their penguin contributions are classified. We find that decays B^-to a_1^0π^-,\barB^0\to a_1^{\pm}π^{\mp}, B^-\to a_1^-\bar K^0, \bar B^0\to a_1^+K^-, \bar B^0\to f_1\bar K^0, B^-\to f_1K^-, B^-\to K_1^-(1400)\etap, B^-\to b_1^-\bar K^{0}, and \bar B^0\to b_1^+π^-(K^-) have branching ratios of the order of 10^{-5}. We also study the dependence of branching ratios for B \to K_1P(V,A) decays (K_1=K_1(1270),K_1(1400)) with respect to the mixing angle between K_A and K_B.

hep-ph↗
arXiv2002

Remarks on Semileptonic B and D Decays into Orbitally Excited Mesons

We have obtained the differential decay rate and calculated the branching ratios of the exclusive semileptonic decays $B(D) \to Xlν$, where $X$ is a p-wave meson, using the nonrelativistic ISGW quark model. Our results are compared with the predictions of the ISGW2 model. We have computed some branching ratios that were not reported or were reported with 0.00 in this model. For example, we find that $Br(B_c^- \to \bar{B_{s2}^{*0}}l^-\barν) = 4.03 \times 10^{-5}$, $Br(B_c^- \to \bar{B_2^{*0}}l^- \barν) =3.65 \times 10^{-6}$ and $Br(D_s^+ \to f_2l^+ν) = 2.7 \times 10^{-5}$, which seems to be at the reach of forthcoming experiments. Furthermore, we have classified the $B_{u,d,s} \to Tlν$ decays in two groups and compared the semileptonic and nonleptonic decays including a tensor meson in the final state.

hep-ph↗
arXiv2002

Non-leptonic decays of the B_c into tensor mesons

We have computed the branching ratios of the exclusive pseudoscalar (vector) + tensor modes that are allowed in the decays of the B_c meson. The dominant spectator and annihilation contributions in those decays are evaluated using the factorization hypothesis. We find that some of these decay channels, such as B_c --> (ρ^-, D_s^{*-}, D_s^{-})χ_{c2} and B_c^ -->π^- \bar{B_{s2}^{*0}}, have branching ratios of the order of 10^{-4}, which seems to be at the reach of forthcoming experiments at the LHC. The inclusive branching fraction of the two-body B_c decays involving tensor particles is approximately 1.28 x10^{-3}. At the dynamical level, it is interesting to observe that the exclusive decays B_c --> K^-(π^-)\bar{D_2^{*0}}, π^0 D_2^{*-}, η^{'} D_{s2}^{*-} are dominated by the annihilation contributions.

hep-ph↗
arXiv1998

Cabibbo-suppressed non-leptonic B- and D-decays involving tensor mesons

The Cabibbo-suppressed non-leptonic decays of B (and D) mesons to final states involving tensor mesons are computed using the non-relativistic quark model of Isgur-Scora-Grinstein-Wise with the factorization hypothesis. We find that some of these B decay modes, as B --> (K^*, D^*)D^*_2, can have branching ratios as large as 6 x 10^{-5} which seems to be at the reach of future B factories.

hep-ph↗
arXiv1998

Mixing of two-level unstable systems

Unstable particles can be consistently described in the framework of quantum field theory. Starting from the full S-matrix amplitudes of B^+ --> (2 pi, 3 pi) l nu decays as examples in the energy region where the rho-omega resonances are dominating, we propose a prescription for the mixing of two quasi `physical' unstable states that differs from the one obtained from the diagonalization of the M -i*Gamma/2 non-hermitian hamiltonian. We discuss some important consequences for CP violation in the K_L - K_S system.

hep-ph↗
arXiv1998

FCNC in leptonic and semileptonic decays of D mesons in a general two-Higgs doublet model

Large long-distance standard model effects in FCNC semileptonic D decays can make observable these processes in future measurements. Eventual disagreements in this sector and/or the observation of lepton family violating (LFV) D decays would require an explanatio beyond the SM framework. In this paper we confront present experimental data on leptonic and semileptonic FCNC and LFV D meson decays with a version of the two-Higgs doublet model that allows these effects to occur at tree- level. The stringent bounds on the parameters of the model are obtained from D^0 --> l^+l'^- and D --> pi l^+l'^- decays. The consistency of the model requires that the branching fractions of D --> V l^+l'^- decays should be below the 10^{-9} level.

hep-ph↗
arXiv1998

The Faddeev-Popov term reviewed

Some textbooks and reports claim that the Jacobian which arises in the discussion of the Faddeev-Popov method to quantize non-Abelian gauge theories and which is given by the derivative of the gauge fixing conditions over the gauge group parameters, is gauge invariant. Other references however prove the opposite. In this brief report we present a discussion about this matter.

hep-th↗
arXiv1997

Further remarks on isospin breaking in charmless semileptonic B decays

We consider the isospin breaking corrections to charmless semileptonic decays of B mesons. Both, the recently measured branching ratios of exclusive decays by the CLEO Collaboration and the end-point reion of the inclusive lepton spectrum in form factor models, can be affected by these corrections. Isospin corrections can affect the determination of |V_ub| from exclusive semileptonic B decays at a level comparable to present statistical uncertainties.

hep-ph↗
arXiv1997

Non-leptonic B decays involving tensor mesons

Two-body non-leptonic decays of B mesons into PT and VT modes are calculated using the non-relativistic quark model of Isgur et al.. The predictions obtained for $B \to πD^*_2, ρD_2^*$ are a factor of $3\sim 5$ below present experimental upper limits. Interesting patterns are obtained for ratios of B decays involving mesons with different spin excitations and their relevance for additional tests of forms factor models are briefly discussed.

hep-ph↗