arXiv subjects

Lorenzo Luis Salcedo

Publications and source records attributed to Lorenzo Luis Salcedo.

11 recordsLinked to original sources

arXiv2018

Schwinger-Dyson equations and line integrals

The Complex Langevin (CL) method sometimes shows convergence to the wrong limit, even though the Schwinger-Dyson Equations (SDE) are fulfilled. We analyze this problem in a more general context for the case of one complex variable. We prove a theorem that shows that under rather general conditions not only the equilibrium measure of CL but any linear functional satisfying the SDE on a space of test functions is given by a linear combination of integrals along paths connecting the zeroes of the underlying measure and noncontractible closed paths. This proves rigorously a conjecture stated long ago by one us (L.~L.~S.) and explains a fact observed in nonergodic cases of CL. one us (L.~L.~S.) and explains a fact observed in nonergodic cases of CL.

math-ph↗

arXiv2017

Thermodynamic characterizations of exotic and missing states

Thermal shifts and fluctuations at finite temperature below the deconfinement crossover of QCD from hadronic matter to the Quark-Gluon Plasma provide a viable way to look for exotic and missing states with given quantum numbers in the hadronic spectrum. We study a realization of the Hadron Resonance Gas model in the light quark ($uds$) flavor sector of QCD to study: i) the entropy shifts, and ii) the fluctuations of electric charge, baryon number and strangeness; and extract from them the possible existence of missing and exotic states from a comparison with lattice data. The analysis of the entropy shift based on the free energy of the Polyakov loop suggests the existence of exotic hybrids $g q \bar q$ and $gqqq$.

hep-ph↗

arXiv2016

Heavy Quark Coupled Channel Dynamics from Thermal Shifts

QCD at finite temperature below the phase transition should be determined in terms of colour singlet states such as hadrons and strings. We show how quark-hadron duality allows extracting sensible information concerning heavy quark and string breaking coupled channel dynamics from Polyakov loop correlators.

hep-ph↗

arXiv2015

Heavy Hadrons in Dense Matter

We study the behavior of dynamically-generated baryon resonances with heavy-quark content within a unitarized coupled-channel theory in matter that fulfills heavy-quark spin symmetry constraints. We analyze the implications for the formation of charmed mesic nuclei and the propagation of heavy mesons in heavy-ion collisions from RHIC to FAIR.

nucl-th↗

arXiv2014

Heavy Mesons in Nuclear Matter and Nuclei

Heavy mesons in nuclear matter and nuclei are analyzed within different frameworks, paying a special attention to unitarized coupled-channel approaches. Possible experimental signatures of the properties of these mesons in matter are addressed, in particular in connection with the future FAIR facility at GSI.

nucl-th↗

arXiv2014

Leptonic CP violating effective action for Dirac and Majorana neutrinos

In the Standard Model minimally extended to include massive neutrinos, we compute the leading CP-violating zero temperature contributions to the one-loop effective action induced by integration of the leptons. Such contributions start at operators of dimension six and they are P even for Dirac neutrinos and P even or odd for Majorana neutrinos. Dimension four operators are allowed in the mixed Dirac-Majorana case. It is verified by explicit calculation that CP can be violated in two generation settings for Majorana neutrinos. Using different neutrino scenarios we give upper bounds for the couplings of the CP-violating operators. As a rule, we find that lepton-induced couplings are suppressed as compared to quark-induced couplings, whenever the latter are allowed, nevertheless, through virtual lepton-number violating mechanisms, Majorana neutrinos induce new CP-violating operators not present in the quark or Dirac-neutrino cases.

hep-ph↗

arXiv2014

Dynamically-generated baryon resonances with heavy flavor

We study baryon resonances with heavy flavor in a molecular approach, thus as dynamically generated by meson-baryon scattering. This is accomplished by using a unitary coupled-channel model taking, as bare interaction, the extension to four flavors and spin symmetry of the Weinberg-Tomozawa interaction potential. A special attention is paid to the inclusion of heavy-quark spin symmetry and to the studies of the generated baryon resonances which complete the heavy-quark spin multiplets. We reproduce few charmed and strange baryon resonances found experimentally, that is, Λ_c(2595), Λ_c(2625), Ξ_c(2790), Ξ_c(2815), and make predictions for more states. The bottom-flavored Λ_b(5912) and Λ_b(5920) states, found by the LHCb collaboration, are also obtained by our model, thus these resonances can be interpreted as molecular states. We also study Ξ_b resonances, which belong to the same SU(3) x HQSS multiplets as the observed Λ_b particles. Finally we analyze hidden-charm baryon resonances. In this sector, we predict seven N-like and five Δ-like states with masses around 4 GeV, most of them as bound states, and compare them with predictions from other models. The predicted states can be searched for in future experiments that involve studies of heavy-flavor physics, e.g. PANDA/FAIR, where charm physics will be analyzed.

hep-ph↗

arXiv2013

N and $Δ$ hidden-charm resonances with heavy-quark spin symmetry

We study N and $Δ$ hidden-charm baryon resonances that are generated dynamically from the s-wave interaction of pseudoscalar and vector mesons with $1/2^+$ and $3/2^+$ baryons. We use a unitary coupled-channels model that fulfills heavy-quark spin symmetry and respects spin-flavor symmetry in the light sector. We predict seven N-like and five $Δ$-like states with masses around 4 GeV, most of them as bound states. Some of these states form heavy-quark spin multiplets, which are almost degenerate in mass.

hep-ph↗

arXiv2013

Heavy-quark spin symmetry for charmed and strange baryon resonances

We study charmed and strange baryon resonances that are generated dynamically by a unitary baryon-meson coupled-channels model which incorporates heavy-quark spin symmetry. This is accomplished by extending the SU(3) Weinberg-Tomozawa chiral Lagrangian to SU(8) spin-flavor symmetry plus a suitable symmetry breaking. The model generates resonances with negative parity from the s-wave interaction of pseudoscalar and vector mesons with 1/2+ and 3/2+ baryons in all the isospin, spin, and strange sectors with one, two, and three charm units. Some of our results can be identified with experimental data from several facilities, such as the CLEO, Belle, or BaBar Collaborations, as well as with other theoretical models, whereas others do not have a straightforward identification and require the compilation of more data and also a refinement of the model.

hep-ph↗

arXiv2013

Review of low-energy interaction of strange and charm hadrons with nucleons and nuclei

The properties of strange and charm mesons in nuclear matter and nuclei are reviewed. Different frameworks are presented and discussed paying a special attention to unitarized coupled-channel approaches. Possible experimental signatures of the in-medium properties of these mesons are also addressed, in particular in connection with the future FAIR facility at GSI.

nucl-th↗

arXiv2012

Strangeness and Charm in Nuclear Matter

The properties of strange ($K$, $\bar K$ and $\bar K^*$) and open-charm ($D$, $\bar D$ and $D^*$) mesons in dense matter are studied using a unitary approach in coupled channels for meson-baryon scattering. In the strangeness sector, the interaction with nucleons always comes through vector-meson exchange, which is evaluated by chiral and hidden gauge Lagrangians. For the interaction of charmed mesons with nucleons we extend the SU(3) Weinberg-Tomozawa Lagrangian to incorporate spin-flavor symmetry and implement a suitable flavor symmetry breaking. The in-medium solution for the scattering amplitude accounts for Pauli blocking effects and meson self-energies. On one hand, we obtain the $K$, $\bar K$ and $\bar K^*$ spectral functions in the nuclear medium and study their behaviour at finite density, temperature and momentum. We also make an estimate of the transparency ratio of the $γA \to K^+ K^{*-} A^\prime$ reaction, which we propose as a tool to detect in-medium modifications of the $\bar K^*$ meson. On the other hand, in the charm sector, several resonances with negative parity are generated dynamically by the s-wave interaction between pseudoscalar and vector meson multiplets with $1/2^+$ and $3/2^+$ baryons. The properties of these states in matter are analyzed and their influence on the open-charm meson spectral functions is studied. We finally discuss the possible formation of $D$-mesic nuclei at FAIR energies.

nucl-th↗