Search

We have studied the contribution of the state X(3930), coming from the interaction of the $$D \overline{D}$$ D D ¯ and $$D^{+}_s D^{-}_s$$ D s + D s - channels, to the $$B^- \rightarrow K^- J/\psi \omega $$ B - → K - J / ψ ω decay. The purpose of this work is to offer a complementary tool to see if the X(3930) state observed in the $$D^+ D^-$$ D + D - channel is the same or not as the X(3960) resonance claimed by the LHCb Collaboration from a peak in the $$D^{+}_s D^{-}_s$$ D s + D s - mass distribution around threshold. We present results for what we expect in the $$J/\psi \omega $$ J / ψ ω mass distribution in the $$B^- \rightarrow K^- J/\psi \omega $$ B - → K - J / ψ ω decay and conclude that a clear signal should be seen around $$3930\,\text {MeV}$$ 3930 MeV . At the same time, finding no extra resonance signal at $$3960\,\text {MeV}$$ 3960 MeV would be a clear indication that there is not a new state at $$3960\,\text {MeV}$$ 3960 MeV , supporting the hypothesis that the near-threshold peaking structure peak in the $$D^{+}_s D^{-}_s$$ D s + D s - mass distribution is only a manifestation of a resonance below threshold.

We have studied the contribution of the state $X(3930)$, coming from the interaction of the $D \overline{D}$ and $D^{+}_s D^{-}_s$ channels, to the $B^- \to K^- J/ψω$ decay. The purpose of this work is to offer a complementary tool to see if the $X(3930)$ state observed in the $D^+ D^-$ channel is the same or not as the $X(3960)$ resonance claimed by the LHCb collaboration from a peak in the $D^{+}_s D^{-}_s$ mass distribution around threshold. We present results for what we expect in the $J/ψω$ mass distribution in the $B^- \to K^- J/ψω$ decay and conclude that a clear signal should be seen around $3930\,\rm MeV$. At the same time, finding no extra resonance signal at $3960\,\rm MeV$ would be a clear indication that there is not a new state at $3960\,\rm MeV$, supporting the hypothesis that the near-threshold peaking structure peak in the $D^{+}_s D^{-}_s$ mass distribution is only a manifestation of a resonance below threshold., 15 pages; 10 figures; new version with improved discussion related to available experimental results

We study the $d^2 Γ_d /(dωd\cosθ_d) $, $dΓ_d /d\cosθ_d$ and $ dΓ_d /dE_d $ distributions, which are defined in terms of the visible energy and polar angle of the charged particle from the $τ-$decay in $b\to c τ\, (μ\bar ν_μν_τ,πν_τ,ρν_τ) \barν_τ$ reactions. The first two contain information on the transverse tau-spin, tau-angular and tau-angular-spin asymmetries of the $H_b\to H_cτ\barν_τ$ parent decay and, from a dynamical point of view, they are richer than the commonly used one, $d^2 Γ_d /(dωdE_d) $, since the latter only depends on the tau longitudinal polarization. We pay attention to the deviations with respect to the predictions of the standard model (SM) for these new observables, considering new physics (NP) operators constructed using both right- and left-handed neutrino fields, within an effective field-theory approach. We present results for $Λ_b\toΛ_cτ\, (μ\bar ν_μν_τ,πν_τ,ρν_τ)\barν_τ$ and $\bar B \to D^{(*)}τ\, (μ\bar ν_μν_τ,πν_τ,ρν_τ) \barν_τ$ sequential decays and discuss their use to disentangle between different NP models. In this respect, we show that $dΓ_d /d\cosθ_d$, which should be measured with sufficiently good statistics, becomes quite useful, especially in the $τ\to πν_τ$ mode. The study carried out in this work could be of special relevance due to the recent LHCb measurement of the lepton flavor universality ratio ${\cal R}_{Λ_c}$ in agreement with the SM. The experiment identified the $τ$ using its hadron decay into $π^-π^+π^-ν_τ$, and this result for ${\cal R}_{Λ_c}$, which is in conflict with the phenomenology from the $b$-meson sector, needs confirmation from other tau reconstruction channels., 20 latex pages, 10 figures, 5 tables, presentation of figures 3 and 4 has changed, new comments and a new reference added

T and B cells employ integrin α4β7 to migrate to intestine under homeostatic conditions. Whether those cells differentially rely on α4β7 for homing during inflammatory conditions has not been fully examined. This may have implications for our understanding of the mode of action of anti-integrin therapies in inflammatory bowel disease (IBD). Here, we examined the role of α4β7 integrin during chronic colitis using IL-10−/− mice, β7-deficient IL-10−/−, IgA-deficient IL-10−/− mice, and antibody blockade of MAdCAM-1. We found that α4β7 was predominantly expressed by B cells. β7 deficiency and MAdCAM-1 blockade specifically depleted antibody secreting cells (ASC) (not T cells) from the colonic LP, leading to a fecal pan-immunoglobulin deficit, severe colitis, and alterations of microbiota composition. Colitis was not due to defective regulation, as dendritic cells (DC), regulatory T cells, retinaldehyde dehydrogenase (RALDH) expression, activity, and regulatory T/B-cell cytokines were all comparable between the strains/treatment. Finally, an IgA deficit closely recapitulated the clinical phenotype and altered microbiota composition of β7-deficient IL-10−/− mice. Thus, a luminal IgA deficit contributes to accelerated colitis in the β7-deficient state. Given the critical/nonredundant dependence of IgA ASC on α4β7:MAdCAM-1 for intestinal homing, B cells may represent unappreciated targets of anti-integrin therapies. © 2021, This is a U.S. government work and not under copyright protection in the U.S.; foreign copyright protection may apply.

We study the behavior of the χc1(3872), also known as X(3872), in dense nuclear matter. We begin from a picture in vacuum of the X(3872) as a purely molecular (DD¯*-c.c.) state, generated as a bound state from a heavy-quark symmetry leading-order interaction between the charmed mesons, and analyze the DD¯* scattering T matrix (TDD¯*) inside of the medium. Next, we consider also mixed-molecular scenarios and, in all cases, we determine the corresponding X(3872) spectral function and the DD¯* amplitude, with the mesons embedded in the dense environment. We find important nuclear corrections for TDD¯* and the pole position of the resonance, and discuss the dependence of these results on the DD¯* molecular component in the X(3872) wave function. These predictions could be tested in the finite-density regime that can be accessed in the future CBM and PANDA experiments at the Facility for Antiproton and Ion Research (FAIR).