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A comment on hadronic charm decays

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 Added by Maurizio Lusignoli
 Publication date 2002
  fields
and research's language is English




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We give arguments in favor of the compatibility with standard physics of some large nonleptonic branching fractions in Cabibbo--forbidden $D^+$ decays, contrary to a recent claim in the literature.



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The FOCUS photoproduction experiment took data in the ninenties and produced a wealth of results in charm physics. Some of the studies were seminal for contemporary experiments, and even paved the way for the technology of many charm and beauty analysis tools.
43 - Ulrich Nierste 2020
I discuss hadronic decays of $D$ mesons with emphasis on the recent discovery of charm CP violation in $D^0to K^+K^-,pi^+pi^-$ decays. The measured difference $Delta a_{CP} , equiv ; a_{CP}^{mathrm{dir}}(D^0rightarrow K^+K^-) - a_{CP}^{mathrm{dir}}(D^0rightarrowpi^+pi^-) = ; (-15.4pm 2.9)cdot 10^{-4}$ of two direct CP asymmetries exceeds the SM prediction by a factor of 7. A possible explanation is an enhancement of the penguin amplitude entering $ a_{CP}^{mathrm{dir}}$ by QCD effects which are not understood yet. Alternatively, $Delta a_{CP}$ could be dominated by contributions from new physics. In order to distinguish these two hypotheses further CP asymmetries should be measured. To this end CP asymmetries resulting from the interference of two tree-level amplitudes auch as $a_{CP}^{mathrm{dir}}(D^0rightarrow K_SK_S)$ or $a_{CP}^{mathrm{dir}}(D^0 to K^{*0} K_S)$ are especially interesting.
At the chiral restoration/deconfinement transition, most hadrons undergo a Mott transition from being bound states in the confined phase to resonances in the deconfined phase. We investigate the consequences of this qualitative change in the hadron spectrum on final state interactions of charmonium in hot and dense matter, and show that the Mott effect for D-mesons leads to a critical enhancement of the J/Psi dissociation rate. Anomalous J/Psi suppression in the NA50 experiment is discussed as well as the role of the Mott effect for the heavy flavor kinetics in future experiments at the LHC. The status of our calculations of hadron-hadron cross sections using the quark interchange and chiral Lagrangian approaches is reviewed, and an Ansatz for a unification of these schemes is given.
82 - Are R. Raklev 2007
We present our work on reconstructing sparticle masses in purely hadronic decay chains, using the $k_T$ jet-algorithm on Monte Carlo simulated events at LHC energies.
116 - Hua-Xing Chen 2021
There are eighteen possibly existing $D^{(*)} bar D^{(*)}$, $D^{(*)} bar K^{(*)}$, and $D^{(*)} D_s^{(*)-}$ hadronic molecular states. We construct their corresponding interpolating currents, and calculate their masses and decay constants using QCD sum rules. Based on these results, we calculate their relative production rates in $B$ and $B^*$ decays through the current algebra, and calculate their relative branching ratios through the Fierz rearrangement, as summarized in Table III. Our results support the interpretations of the $X(3872)$, $Z_c(3900)$, $Z_c(4020)$, and $X_0(2900)$ as the molecular states $D bar D^*$ of $J^{PC} = 1^{++}$, $D bar D^*$ of $J^{PC} = 1^{+-}$, $D^* bar D^*$ of $J^{PC} = 1^{+-}$, and $D^* bar K^*$ of $J^P = 0^{+}$, respectively. Our results also suggest that the $Z_{cs}(3985)$, $Z_{cs}(4000)$, and $Z_{cs}(4220)$ are strange partners of the $X(3872)$, $Z_c(3900)$, and $Z_c(4020)$, respectively. In the calculations we estimate the lifetime of a weakly-coupled composite particle $A = |BCrangle$ to be $1/t_A approx 1/t_B + 1/t_C + Gamma_{A to BC} + cdots$, with $cdots$ partial widths of other possible decay channels.
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