Triangle singularity in the J/ψ → K+K− f0(980) decay

2020

Weak decays of heavy hadrons into dynamically generated resonances

2016

In this paper, we present a review of recent works on weak decay of heavy mesons and baryons with two mesons, or a meson and a baryon, interacting strongly in the final state. The aim is to learn about the interaction of hadrons and how some particular resonances are produced in the reactions. It is shown that these reactions have peculiar features and act as filters for some quantum numbers which allow to identify easily some resonances and learn about their nature. The combination of basic elements of the weak interaction with the framework of the chiral unitary approach allow for an interpretation of results of many reactions and add a novel information to different aspects of the hadron…

The role of N*(2120) nucleon resonance in KΛ(1520) photon and hadronic productions

2013

The associate $K\Lambda(1520)$ photon and hadronic production in the $\gamma p \to K^+\Lambda(1520)$, $p p \to p K^+ \Lambda(1520)$ and $\pi^- p \to K^0 \Lambda(1520)$ reactions are investigated within the effective Lagrangian approach and the isobar model. We are interested in the contribution from the $N^*(2120)$ (previously called $N^*(2080)$) resonance, which has a significant coupling to the $K\Lambda(1520)$ channel. The theoretical results show that the current experimental data for the $\gamma p \to K^+\Lambda(1520)$ reaction favor the existence of the $N^*(2120)$ resonance, and that these measurements can be used to further constrain its properties. We present results, including the…

Λb→J/ψK0Λreaction and a hidden-charm pentaquark state with strangeness

2016

We study the Lambda(b) -> J/psi K-0 Lambda reaction considering both the K-0 Lambda interaction with its coupled channels and the J/psi Lambda interaction. The latter is described by taking into account the fact that there are predictions for a hidden-charm state with strangeness that couples to J/psi Lambda By using the coupling of the resonance to J/psi Lambda from these predictions, we show that a neat peak can be observed in the J/psi Lambda invariant mass distribution, rather stable under changes of unknown magnitudes. In some cases, one finds a dip structure associated to that state, but a signal of the state shows up in the J/psi Lambda spectrum.

The role of X(4140) and X(4160) in the reactions of B+→J/ψϕK+

2020

Electroweak processes in nucleons and nuclei at intermediate energies

2014

263 páginas. Tesis Doctoral del Departamento de Física Teórica de la Universidad de Valencia y del Instituto de Física Corpuscular (IFIC).

Role of theΔ*(1940)in theπ+p→K+Σ+(1385)andpp→nK+Σ+(1385)reactions

2014

The pp -> nK(+)Sigma(+)(1385) reaction is a very good isospin 3/2 filter for studying Delta(++)* resonance decaying to K+Sigma(+)(1385). Within the effective Lagrangian method, we investigate the Sigma (1385) (spin parity J(P) = 3/2(+)) hadronic production in the pi(+) p -> K+Sigma(+)(1385) and pp -> nK(+)Sigma(+)(1385) reactions. For the pi(+) p -> K+Sigma(+)(1385) reaction, in addition to the "background" contributions from t-channel K*(0) exchange and u-channel Lambda(1115) and Sigma(0)(1193) exchange, we also consider the contribution from the s-channel Delta*(1940) resonance, which has significant coupling to the K Sigma(1385) channel. We show that the inclusion of the Delta*(1940) res…

Single photon production induced by (anti)neutrino neutral current scattering on nucleons and nuclear targets

2015

We review our theoretical approach to neutral current photon emission on nucleons and nuclei in the few-GeV energy region, relevant for neutrino oscillation experiments. These reactions are dominated by the weak excitation of the $\Delta(1232)$ resonance but there are also important non-resonant contributions. We have also included terms mediated by nucleon excitations from the second resonance region. On nuclei, Pauli blocking, Fermi motion and the in-medium $\Delta$ resonance broadening have been taken into account for both incoherent and coherent reaction channels. With this model, the number and distributions of photon events at the MiniBooNE and T2K experiments have been obtained. We h…

Analysis of the B+→J/ψϕK+ data at low J/ψϕ invariant masses and the X(4140) and X(4160) resonances

2018

We have studied the $J/\ensuremath{\psi}\ensuremath{\phi}$ mass distribution of the ${B}^{+}\ensuremath{\rightarrow}J/\ensuremath{\psi}\ensuremath{\phi}{K}^{+}$ reaction from threshold to about 4250 MeV, and find that one needs the contribution of the $X(4140)$ with a narrow width, together with the $X(4160)$ which accounts for most of the strength of the distribution in that region. The existence of a clear cusp at the ${D}_{s}^{*}{\overline{D}}_{s}^{*}$ threshold indicates that the $X(4160)$ resonance is strongly tied to the ${D}_{s}^{*}{\overline{D}}_{s}^{*}$ channel, which finds a natural interpretation in the molecular picture of this resonance.

Calibration strategy of the JUNO experiment

2021

We present the calibration strategy for the 20 kton liquid scintillator central detector of the Jiangmen Underground Neutrino Observatory (JUNO). By utilizing a comprehensive multiple-source and multiple-positional calibration program, in combination with a novel dual calorimetry technique exploiting two independent photosensors and readout systems, we demonstrate that the JUNO central detector can achieve a better than 1% energy linearity and a 3% effective energy resolution, required by the neutrino mass ordering determination. [Figure not available: see fulltext.]

The Design and Sensitivity of JUNO's scintillator radiopurity pre-detector OSIRIS

2021

The European physical journal / C 81(11), 973 (2021). doi:10.1140/epjc/s10052-021-09544-4

Radioactivity control strategy for the JUNO detector

2021

JUNO is a massive liquid scintillator detector with a primary scientific goal of determining the neutrino mass ordering by studying the oscillated anti-neutrino flux coming from two nuclear power plants at 53 km distance. The expected signal anti-neutrino interaction rate is only 60 counts per day, therefore a careful control of the background sources due to radioactivity is critical. In particular, natural radioactivity present in all materials and in the environment represents a serious issue that could impair the sensitivity of the experiment if appropriate countermeasures were not foreseen. In this paper we discuss the background reduction strategies undertaken by the JUNO collaboration…

Single photon events from neutral current interactions at MiniBooNE

2014

The MiniBooNE experiment has reported results from the analysis of $\nu _e$ and $\bar \nu _e$ appearance searches, which show an excess of signal-like events at low reconstructed neutrino energies, with respect to the expected background. A significant component of this background comes from photon emission induced by (anti)neutrino neutral current interactions with nucleons and nuclei. With an improved microscopic model for these reactions, we predict the number and distributions of photon events at the MiniBooNE detector. Our results are compared to the MiniBooNE in situ estimate and to other theoretical approaches. We find that, according to our model, neutral current photon emission fro…

Regge signatures from CLAS Λ(1520) photoproduction data at forward angles

2014

The γp→K+Λ(1520) reaction mechanism is investigated within a Regge-effective Lagrangian hybrid approach based on our previous study of this reaction [Phys. Rev. C 89, 015203 (2014)PRVCAN0556-281310.1103/PhysRevC.89.015203]. Near threshold and for large K+ angles, the data from both the Continuous Electron Beam Accelerator Facility large acceptance spectrometer (CLAS) and the laser electron photon beamline at SPring-8 (LEPS) can be successfully described by considering the contributions from the contact, t-channel K¯ exchange, u-channel Λ(1115) hyperon pole, and s-channel nucleon pole and N*(2120) resonance contributions. However, for higher energies and forward K+ angles, systematic discrep…

Re-analysis of theΛ(1520)photoproduction reaction

2014

Based on previous studies that support the important role of the N*(2120)D-13 resonance in the gamma p -> K+ A(1520) reaction, we make a re-analysis of this A(1520) photoproduction reaction taking into account the recent CLAS differential cross-section data. In addition to the contact, t-channel (K) over bar exchange, s-channel nucleon pole, and N*(2120) [previously called N*(2080)] resonance contributions, which have been considered in previous works, we also study the u-channel A(1115) hyperon pole term. The latter mechanism has always been ignored in all theoretical analysis, which has mostly relied on the very forward K+ angular LEPS data. It is shown that when the contributions from th…

JUNO sensitivity to low energy atmospheric neutrino spectra

2021

Atmospheric neutrinos are one of the most relevant natural neutrino sources that can be exploited to infer properties about cosmic rays and neutrino oscillations. The Jiangmen Underground Neutrino Observatory (JUNO) experiment, a 20 kton liquid scintillator detector with excellent energy resolution is currently under construction in China. JUNO will be able to detect several atmospheric neutrinos per day given the large volume. A study on the JUNO detection and reconstruction capabilities of atmospheric $\nu_e$ and $\nu_\mu$ fluxes is presented in this paper. In this study, a sample of atmospheric neutrino Monte Carlo events has been generated, starting from theoretical models, and then pro…

Predictions for pentaquark states of hidden charm molecular nature and comparison with experiment

2016

Predictions for hidden charm molecules, with and without strangeness, were made prior to the LHCb experiment. We discuss these issues and how these states can be observed in the reactions, Λ b → J / ψK − p , Λ b → J / ψη Λ, Λ b → J / ψπ − p , Λ b → J / ψK 0 Λ and Ξ − b → J / ψK − Λ by looking at the invariant mass distributions for J / ψp or J / ψ Λ.

χ c0 (1 P ) decay intoΣ¯ Σπin search of an I = 1, 1/2 − baryon state aroundK¯Nthreshold

2016

Abstract We present the theoretical study of the process χ c 0 ( 1 P ) → Σ ¯ Σ π decay, by taking into account the π Σ and π Σ ¯ final state interactions of the final meson-baryon pair based on the chiral unitary approach. We show that the process filters the isospin I = 1 in the π Σ channel and offers a reaction to test the existence of an I = 1 state with strangeness S = − 1 and spin-parity J p = 1 / 2 − around the K ¯ N threshold predicted by some theories and supported by some experiments.

Study of reactions disclosing hidden charm pentaquarks with or without strangeness

2016

We present results for five reactions, Lambda(b) -> J/psi K(-)p, Lambda(b) -> J/psi eta Lambda, Lambda(b) -> J/psi pi(-)p, Lambda(b) -> J/psi K-0 Lambda and Xi(-)(b) -> J/psi K-Lambda, where combining information from the meson baryon interaction, using the chiral unitary approach, and predictions made for molecular states of hidden charm, with or without strangeness, we can evaluate invariant mass distributions for the light meson baryon states, and for those of J/psi p or J/psi Lambda. We show that with the present available information, in all of these reactions one finds peaks where the pentaquark states show up. In the Lambda(b) -> J/psi K(-)p, and Lambda(b) -> J/psi pi(-)p reactions w…

Analysis of the γγ→DD¯ reaction and the DD¯ bound state

2021

In this work, we investigate the reaction of $\ensuremath{\gamma}\ensuremath{\gamma}\ensuremath{\rightarrow}D\overline{D}$, taking into account the $S$-wave $D\overline{D}$ final state interaction. By fitting to the $D\overline{D}$ invariant mass distributions measured by the Belle and BABAR Collaborations, we obtain a good reproduction of the data by means of a $D\overline{D}$ amplitude that produces a bound $D\overline{D}$ state with isospin $I=0$ close to threshold. The error bands of the fits indicate, however, that more precise data on this reaction are needed to be more assertive about the position and width of such a state.

Low-lying even parity meson resonances and spin-flavor symmetry revisited

2013

We review and extend the model derived in Garcia-Recio et al. [Phys. Rev. D 83, 016007 (2011)] to address the dynamics of the low-lying even-parity meson resonances. This model is based on a coupled-channels spin-flavor extension of the chiralWeinberg-Tomozawa Lagrangian. This interaction is then used to study the S-wave meson-meson scattering involving members not only of the pi octet, but also of the rho nonet. In this work, we study in detail the structure of the SU(6)-symmetry-breaking contact terms that respect (or softly break) chiral symmetry. We derive the most general local (without involving derivatives) terms consistent with the chiral-symmetry-breaking pattern of QCD. After intr…

Hidden-charm pentaquark state inΛb0→J/ψpπ−decay

2016

We study here the ${\mathrm{\ensuremath{\Lambda}}}_{b}^{0}\ensuremath{\rightarrow}J/\ensuremath{\psi}p{\ensuremath{\pi}}^{\ensuremath{-}}$ reaction in analogy to the ${\mathrm{\ensuremath{\Lambda}}}_{b}^{0}\ensuremath{\rightarrow}J/\ensuremath{\psi}p{K}^{\ensuremath{-}}$ one, and we note that in both decays there is a sharp structure (dip or peak) in the $J/\ensuremath{\psi}p$ mass distribution around 4450 MeV, which is associated in the ${\mathrm{\ensuremath{\Lambda}}}_{b}^{0}\ensuremath{\rightarrow}J/\ensuremath{\psi}p{K}^{\ensuremath{-}}$ experiment to an exotic pentaquark baryonic state, although in ${\mathrm{\ensuremath{\Lambda}}}_{b}^{0}\ensuremath{\rightarrow}J/\ensuremath{\psi}p{\en…

Photon emission in neutral current interactions with nucleons and nuclei

2013

We report on our study of photon emission induced by Enu ~ 1 GeV (anti)neutrino neutral current interactions with nucleons and nuclei. This process is an important background for nu_e appearance oscillation experiments. At the relevant energies, the reaction is dominated by the excitation of the Delta (1232) resonance but there are also non-resonant contributions that, close to threshold, are fully determined by the effective chiral Lagrangian of strong interactions. We have obtained differential and integrated cross section for the (anti)neutrino-nucleon scattering and compare them with previous results. Furthermore, we have extended the model to nuclear targets taking into account Fermi m…

Photon emission in neutral current interactions at the T2K experiment

2015

9 pages.- 6 figures

Tetra and pentaquarks from the molecular perspective

2019

We present results for the analysis of the B+ → J/ψϕK+ which shows the contribution of two resonances, the X(4140) and X(4160) and a cusp at the $D_s^*\bar D_s^*$ threshold tied to the molecular character of the X(4160) resonance. In the second part we present the results for the theoretical approach to the new Ωcstates from the molecular perspective. In both cases we compare with results of the LHCb collaboration.

Looking for a hidden-charm pentaquark state with strangeness $S=-1$ from $\Xi^-_b$ decay into $J/\psi K^- \Lambda$

2015

Assuming that the recently observed hidden-charm pentaquark state, $P_c(4450)$, is of molecular nature as predicted in the unitary approach, we propose to study the decay of $\Xi^-_b\rightarrow J/\psi K^- \Lambda$ to search for the strangeness counterpart of the $P_c(4450)$. There are three ingredients in the decay mechanism: the weak decay mechanism, the hadronization mechanism, and the finite state interactions in the meson-baryon system of strangeness $S=-2$ and isospin $I=1/2$ and of the $J/\psi\Lambda$. All these have been tested extensively. As a result, we provide a genuine prediction of the differential cross section where a strangeness hidden-charm pentaquark state, the counterpart…

Role of the $\Delta^*(1940)$ in the $\pi^+ p \to K^+ \Sigma^+(1385)$ and $pp \to n K^+ \Sigma^+(1385)$ reactions

2014

The $p p \to n K^+ \Sigma^+(1385)$ reaction is a very good isospin $3/2$ filter for studying $\Delta^{++*}$ resonance decaying to $K^+\Sigma^+(1385)$. Within the effective Lagrangian method, we investigate the $\Sigma(1385)$ (spin-parity $J^P = 3/2^+$) hadronic production in the $\pi^+ p \to K^+ \Sigma^+(1385)$ and $p p \to n K^+ \Sigma^+(1385)$ reactions. For $\pi^+ p \to K^+ \Sigma^+(1385)$ reaction, in addition to the "background" contributions from $t$-channel $K^{*0}$ exchange, $u$-channel $\Lambda(1115)$ and $\Sigma^0(1193)$ exchange, we also consider the contribution from the $s$-channel $\Delta^*(1940)$ resonance, which has significant coupling to $K\Sigma(1385)$ channel. We show th…

Signatures of the two $$K_1(1270)$$ K1(1270) poles in $$D^+\rightarrow \nu e^+ V P$$ D+→νe+VP decay

2020

We analyze theoretically the $$D^+\rightarrow \nu e^+ \rho \bar{K}$$ D+→νe+ρK¯ and $$D^+\rightarrow \nu e^+ \bar{K}^* \pi $$ D+→νe+K¯∗π decays to see the feasibility to check the double pole nature of the axial-vector resonance $$K_1(1270)$$ K1(1270) predicted by the unitary extensions of chiral perturbation theory (UChPT). Indeed, within UChPT the $$K_1(1270)$$ K1(1270) is dynamically generated from the interaction of a vector and a pseudoscalar meson, and two poles are obtained for the quantum numbers of this resonance. The lower mass pole couples dominantly to $$K^*\pi $$ K∗π and the higher mass pole to $$\rho K$$ ρK , therefore we can expect that different reactions weighing differently…

Looking for a hidden-charm pentaquark state with strangeness $S=-1$ from $��^-_b$ decay into $J/��K^- ��$

2015

Assuming that the recently observed hidden-charm pentaquark state, $P_c(4450)$, is of molecular nature as predicted in the unitary approach, we propose to study the decay of $��^-_b\rightarrow J/��K^- ��$ to search for the strangeness counterpart of the $P_c(4450)$. There are three ingredients in the decay mechanism: the weak decay mechanism, the hadronization mechanism, and the finite state interactions in the meson-baryon system of strangeness $S=-2$ and isospin $I=1/2$ and of the $J/����$. All these have been tested extensively. As a result, we provide a genuine prediction of the differential cross section where a strangeness hidden-charm pentaquark state, the counterpart of the $P_c(445…

Re-analysis of the $\Lambda(1520)$ photoproduction reaction

2013

Based on previous studies that support the important role of the $N^*(2120) D_{13}$ resonance in the $\gamma p \to K^+ \Lambda(1520)$ reaction, we make a re-analysis of this $\Lambda(1520)$ photoproduction reaction taking into account the recent CLAS differential cross-section data. In addition to the contact, $t-$channel $\bar K$ exchange, $s-$channel nucleon pole and $N^*(2120)$ [previously called $N^*(2080)$] resonance contributions, which have been already considered in previous works, we also study the $u-$channel $\Lambda(1115)$ hyperon pole term. The latter mechanism has always been ignored in all theoretical analysis, which has mostly relied on the very forward $K^+$ angular LEPS da…

A hidden-charm pentaquark state in $\Lambda^0_b \to J/\psi p \pi^-$ decay

2015

We study here the $\Lambda_b^0 \to J/\psi p \pi^-$ reaction in analogy to the $\Lambda^0_b \to J/\psi p K^-$ one, and we note that in both decays there is a sharp structure (dip or peak) in the $J/\psi p$ mass distribution around $4450$ MeV, which is associated in the $\Lambda^0_b \to J/\psi p K^-$ experiment to an exotic pentaquark baryonic state, although in $\Lambda_b^0 \to J/\psi p \pi^-$ it shows up with relatively low statistics. We analyze the $\Lambda^0_b \to J/\psi p \pi^-$ interaction along the same lines as the $\Lambda^0_b \to J/\psi p K^-$ one, with the main difference stemming from the reduced Cabibbo strength in the former and the consideration of the $\pi^-p$ final state int…

$��_{c0}(1P)$ decay into $\bar��~����$ in search of an $I=1$, $1/2^-$ baryon state around $\bar K N$ threshold

2015

We present the theoretical study of the process $��_{c0}(1P)\to\bar������$ decay, by taking into account the $����$ and $��\bar��$ final state interactions of the final meson-baryon pair based on the chiral unitary approach. We show that the process filters the isospin $I=1$ in the $����$ channel and offers a reaction to test the existence of an $I=1$ state with strangeness $S=-1$ and spin-parity $J^p=1/2^-$ around the $\bar KN$ threshold predicted by some theories and supported by some experiments.

$\chi_{c0}(1P)$ decay into $\bar\Sigma~\Sigma\pi$ in search of an $I=1$, $1/2^-$ baryon state around $\bar K N$ threshold

2015

We present the theoretical study of the process $\chi_{c0}(1P)\to\bar\Sigma\Sigma\pi $ decay, by taking into account the $\pi\Sigma$ and $\pi\bar\Sigma$ final state interactions of the final meson-baryon pair based on the chiral unitary approach. We show that the process filters the isospin $I=1$ in the $\pi\Sigma$ channel and offers a reaction to test the existence of an $I=1$ state with strangeness $S=-1$ and spin-parity $J^p=1/2^-$ around the $\bar KN$ threshold predicted by some theories and supported by some experiments.

Regge signatures from forward CLAS $\Lambda(1520)$ photoproduction data

2014

The $\gamma p \to K^+ \Lambda(1520)$ reaction mechanism is investigated within a Regge--effective Lagrangian hybrid approach based on our previous study of this reaction [Physical Review C89, 015203 (2014)]. Near threshold and for large $K^+$ angles, both the CLAS and LEPS data can be successfully described by considering the contributions from the contact, $t$-channel $\bar K$ exchange, $u$-channel $\Lambda(1115)$ hyperon pole, and the $s$-channel nucleon pole and $N^*(2120)$ resonance contributions. However, for higher energies and forward $K^+$ angles, systematic discrepancies with data appear, which hint the possible existence of sizable quark-gluon string mechanism effects. We show how…