Large Branching Ratio Research Articles

Rare B and K decays in a scotogenic model

A scotogenic model can radiatively generate the observed neutrino mass, provide a dark matter candidate, and lead to rare lepton flavor-violating processes. We aim to extend the model to establish a potential connection to the quark flavor-related processes within the framework of scotogenesis, enhancing the unexpectedly large branching ratio (BR) of B+→K+νν¯ observed by the Belle II Collaboration. Meanwhile, the model can address tensions between some experimental measurements and standard model (SM) predictions in flavor physics, such as the muon g−2 excess and the higher BR of Bs→μ−μ+. In the model, we introduce the following dark particles: a neutral singlet Dirac-type lepton (N); two inert Higgs doublets (η1,2), with one carrying a lepton number; a charged singlet dark scalar (χ+); and a singlet vectorlike up-type dark quark (T). The first two entities are responsible for the radiative neutrino mass, and χ+ couples to right-handed quarks and leptons and can resolve the tensions existing in muon g−2 and Bs→μ−μ+. Furthermore, the BR of B+→K+νν¯ can be enhanced up to a factor of 2 compared to the SM prediction through the mediations of the dark T and the charged scalars. In addition, we also study the impacts on the K→πνν¯ decays. Published by the American Physical Society 2024

Exploring the molecular scenario of X(4160)

In this work, we investigate the decays of meson X(4160) in the molecular frame. By using an effective lagrangian approach, we calculate the widths of X(4160)→J/ψϕ\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$X(4160)\\rightarrow J/\\psi \\phi $$\\end{document}, D∗D¯∗\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$D^*\\bar{D}^*$$\\end{document}, D∗D¯\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$D^*\\bar{D}$$\\end{document} and DD¯\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$D\\bar{D}$$\\end{document} through the triangle loop mechanism in the molecular scenario. Based on the compositeness condition, the coupling between X(4160) and the Ds∗D¯s∗\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$D_s^*\\bar{D}_s^*$$\\end{document} molecular state is determined. The other coupling constants used are determined phenomenologically. The calculation of the decay widths shows that the D∗D¯∗\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$D^*\\bar{D}^*$$\\end{document} decay mode has a larger branching ratio. These predictions can be seen as a test for the charmonium assignment of X(4160).

A theoretical study on excited-state dynamical properties and laser cooling of zinc monohydride including spin-orbit couplings.

By means of highly accurate ab initio and dynamical calculations, we identify a suitable laser cooling candidate that contains a transition metal element, namely zinc monohydride (ZnH). The internally contracted multireference configuration interaction method is employed to compute the five lowest-lying Λ-S states of ZnH with the spin-orbit coupling effects included, and very good agreement is obtained between our calculated and experimental spectroscopic data. Our findings show that the position of crossing point of the A2Π and B2Σ+ states of ZnH is above the v' = 2 vibrational level of the A2Π state indicating that the crossings with higher electronic states will have no effect on laser cooling. Hence, we construct a feasible laser-cooling scheme for ZnH using five lasers based on the A2Π1/2 → X2Σ+ 1/2 transition, which features a large vibrational branching ratio R 00 (0.8458), a large number of scattered photons (9.8 × 103) and an extremely short radiative lifetime (64ns). The present work demonstrates the importance of electronic state crossings and spin-orbit couplings in the study of molecular laser cooling.

Custodial symmetry breaking and Higgs boson signatures at the LHC

We discuss the simplest model that predicts a tree-level modification of the ρ parameter from a shift in the W-mass without changing the prediction for the Z mass. This model predicts a new neutral Higgs and two charged Higgses, with very similar masses and suppressed couplings to the Standard Model fermions. We discuss the decay properties of these new scalar bosons, and the main signatures at the Large Hadron Collider. Comparing these signatures for the first time to the latest measurements, we show that while masses around 200 GeV are excluded for some scenarios, over a wide range of model parameter space the new bosons can have a mass close to the electroweak scale without violating existing limits from experimental searches or destroying the agreement with measurements. We investigate the scenario where the new neutral Higgs is fermiophobic and has a large branching ratio into W gauge bosons and/or photons, and show that this could lead to a signal in the diphoton mass spectrum at low Higgs masses. We discuss the different signatures that can motivate new measurements and searches at the Large Hadron Collider. Published by the American Physical Society 2024

Production of Ds0(2590)+\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$D_{s0}(2590)^+$$\\end{document} in B nonleptonic decays

In 2021, a new charm-strange meson, Ds0(2590)+\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$D_{s0}(2590)^+$$\\end{document}, was discovered, which is believed to be the Ds+(21S0)\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$D_s^+(2^1S_0)$$\\end{document}. However, its low mass and wide width are challenged by theoretical results. Given the small branching ratio of the current production channel, resulting in a small number of events and large errors, we suggest searching for the Ds0(2590)+\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$D_{s0}(2590)^+$$\\end{document} in the B meson nonleptonic decays, Bq→Dq(∗)Ds0(2590)+\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$B_q\\rightarrow D^{(*)}_qD_{s0}(2590)^+$$\\end{document} (q=u,d\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$q=u,d$$\\end{document}), followed by Ds0(2590)+→D∗K\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$D_{s0}(2590)^+\\rightarrow D^*K$$\\end{document}. We find that Br(Bq→Dq(∗)Ds0(2590)+)×Br(Ds0(2590)+→D∗K)=(2.16∼2.82)×10-3\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$Br(B_q\\rightarrow D^{(*)}_qD_{s0}(2590)^+)\ imes Br(D_{s0}(2590)^+\\rightarrow D^{*}K)=(2.16\\sim 2.82)\ imes 10^{-3}$$\\end{document} is very large, and the result is not sensitive to the mass of Ds0(2590)+\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$D_{s0}(2590)^+$$\\end{document}. Due to the large branching ratio, numerous Ds0(2590)+\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$D_{s0}(2590)^+$$\\end{document} events are expected. This study is based on the framework of the instantaneous Bethe–Salpeter equation, and the relativistic wave functions used for mesons contain different partial waves. The contributions of the different partial waves are also studied.

Bounding the Dimension-5 Seesaw Portal with non-pointing photon searches

The addition of d = 5 operators to the Seesaw model leads to the Dimension-5 Seesaw Portal. Here, two new operators provide interactions for the heavy sterile neutrinos. In particular, the Higgs boson can have a large branching ratio into two heavy neutrinos, meaning that these states can be searched for at the LHC. Moreover, the heavy neutrinos can now decay dominantly into light neutrinos and photons. If the heavy neutrinos are long-lived, then searches for delayed, non-pointing photons can constrain the model. In this work, we carry out a detailed recast of an ATLAS search for such displaced photons, triggered by a charged lepton produced in association to the Higgs, placing bounds on the branching ratio for Higgs decay into two heavy neutrinos as low as 2%.

A theoretical study on the mechanism and kinetics of the reactions between diazine isomers and OH radicals

AbstractThe reactions of pyrazine, pyridazine, and pyrimidine with hydroxyl radicals are theoretically studied. The barrier heights obtained with different electronic structure methods indicate that the reactions can competitively proceed via either abstraction of a hydrogen atom by an OH radical or OH addition to carbon sites. However, the rate constants computed within the temperature range 200 to 1500 K suggest that tunneling play a role resulting in large branching ratios in favor of hydrogen abstraction channels at lower temperatures.

Detecting the coupling of axion-like particles with fermions at the ILC

New pseudoscalars, axion-like particles (ALPs), provide the exciting target for present and future collider-based experiments. Search for ALPs is performed in this paper via the W+W− fusion process e−e+→νeνe‾a→νeνe‾ff‾ at the 1 TeV ILC corresponding to an integrated luminosity of 1 ab−1 and the beam polarization P(e−, e+)=(−80%, +20%). Owing to the good capability of the ILC in performing b-tagging and the sufficiently large branching ratio of the ALP decaying into a pair of b quarks, the decay channel a→bb‾ is mainly concerned. The prospective sensitivities provided by the ILC on the ALP-fermion coupling as low as 1 TeV−1 and 1.75 TeV−1 are derived at 95% confidence level in the ALP mass intervals 37−50 GeV and 52−300 GeV, respectively. Our results will help to probe significant parameter space in an unexplored region beyond the existing constraints.

The decay A 0 → h 0 Z(∗) in the inverted hierarchy scenario and its detection prospects at the large hadron collider

Searches are being carried out at the large hadron collider (LHC) for the decay of the CP-odd scalar (A 0) in two-Higgs-doublet models (2HDMs) with natural flavour conservation (NFC) in the channel A 0 → h 0 Z (with and Z on-shell). In the absence of any signal, limits on the parameter space of in each 2HDM are derived for . In this work, we consider the scenario of inverted hierarchy with and in which the decay A 0 → h 0 Z(∗) (i.e. including the case of an off-shell Z) can have a large branching ratio in the 2HDM (Type I) for . We calculate the signal cross section in the 2HDM (Type I) with NFC and compare its magnitude with the cross section for the case of normal hierarchy ( GeV) that is currently being searched for at the LHC. For the experimentally unexplored region GeV it is shown that the above cross section for signal events in the scenario of inverted hierarchy can be of the order of a few picobarns. Such sizeable cross sections are several orders of magnitude larger than the cross sections for the case of normal hierarchy, thus motivating an extension of the ongoing searches for A 0 → h 0 Z(∗) to probe the scenario of inverted hierarchy.

Mixing effects of η−η′ in Λb→Λη(′) decays

We perform a thorough analysis of the $\eta-\eta'$ mixing effects on the $\Lambda_b\rightarrow \Lambda \eta^{(')}$ decays based on the perturbative QCD (PQCD) factorization approach. Branching ratios, up-down and direct $CP$ asymmetries are computed by considering four popular mixing schemes, such as $\eta-\eta'$, $\eta-\eta'-\eta_c$, $\eta-\eta'-G$, and $\eta-\eta'-G-\eta_c$ mixing formalism, where $G$ represents the physical pseudoscalar gluball. The PQCD predictions with the four mixing schemes does not change much for the $\eta$ channel but changes significantly for the $\eta'$ one. In particular, the value of $\mathcal{B}(\Lambda_b\rightarrow \Lambda \eta^{'})$ in the $\eta-\eta'-G-\eta_c$ mixing scheme exceeds the present experimental bound by a factor of 2, indicates the related mixing angles may be overestimated. Because of the distinctive patterns of interference between $S$-wave and $P$-wave amplitudes, the predicted up-down asymmetries for the two modes differ significantly. The obvious discrepancies among different theoretical analyses should be clarified in the future. The direct $CP$ violations are predicted to be at the level of a few percent mainly due to the tree contributions of the strange and nonstrange amplitudes suffer from the color suppression and CKM suppression. Finally, as a byproduct, we investigate the $\Lambda_b\rightarrow \Lambda \eta_c$ process, which has a large branching ratio of order $10^{-4}$, promising to be measured by the LHCb experiment. Our findings are useful for constraining the mixing parameters, comprehending the $\eta^{(')}$ configurations, and instructing experimental measurements.

Spectroscopy and 2.8 µm laser operation of disordered Er:CLNGG crystals.

We report on the first, to the best of our knowledge, laser operation on the 4I11/2 → 4I13/2 transition of erbium-doped disordered calcium lithium niobium gallium garnet (CLNGG) crystals with broadband mid-infrared emission properties. A 41.4 at.% Er:CLNGG continuous-wave laser generated 292 mW at 2.80 µm with 23.3% slope efficiency and a laser threshold of 209 mW. Er3+ ions in CLNGG feature inhomogeneously broadened spectral bands (σSE = 1.79 × 10-21 cm2 at 2.79 µm; emission bandwidth, 27.5 nm), a large luminescence branching ratio for the 4I11/2 → 4I13/2 transition of 17.9%, and a favorable ratio of the 4I11/2 and 4I13/2 lifetimes, exhibiting values of 0.34 ms and 1.17 ms (for 41.4 at.% Er3+), respectively.

A Theoretical Study of H-Abstractions of Benzaldehyde by H, O3(P), 3O2, OH, HO2, and CH3 Radicals: Ab Initio Rate Coefficients and Their Uncertainty Quantification.

Benzaldehyde is a vital intermediate during the oxidation of toluene and oxygenated aromatics, but benzaldehyde's combustion chemistry currently gains little attention. The H-atom abstraction of benzaldehyde is one critical reaction class, yet its rate coefficients rely on the analogy of molecular similarity. For this reason, we have employed the ab initio calculations at the CCSD(T)/cc-pVTZ//M06-2X/6-311+g(d,p) level of theory, along with the RRKM master equation to predict the rate coefficients of H-abstraction reactions of benzaldehyde by H, O3(P), 3O2, OH, HO2, and CH3 radicals. The calculated rate coefficients of benzaldehyde + OH generally agree with literature measurements. From the branching ratio analysis, all the H-abstractions from ring sites can be neglected in kinetic model construction except by OH radical at temperature above 1700 K, where the ring sites contribute a relatively large branching ratio to consume benzaldehyde. A random sampling method has been used to estimate the global uncertainty in the calculated rate coefficients. The logarithm of uncertainty is proportional to the reciprocal temperature, and the global uncertainty is primarily derived from the energy errors and is almost independent of the attacking species. Comparison between benzaldehyde and acetaldehyde reveals that their rate coefficients are consistent only in H-abstractions by H and HO2 but are conflictive in other reactions, especially in the case of OH. By incorporating the new calculations, existing models show a faster prediction in autoignition delay times of benzaldehyde. This study reports the first high-level ab initio calculations for the H-atom abstraction reaction class of benzaldehyde. It is necessary for the future comprehensive kinetic modeling of aromatic aldehyde.

Study of heavy quark conserving weak decays in the quark model

Within the framework of a constituent quark model, we investigate the heavy quark conserving weak decays of Ξc and Ξb. This process involves elementary transitions of us→du or s→udu¯ with the heavy quark as a spectator, while for the charmed baryon in the initial state it can also occur via cs→dc to conserve the heavy quark flavor in the weak decays. It shows that the heavy quark symmetry (HQS) plays an essential role in the processes where the heavy quark acts as a spectator. For the Ξc decays, the dominance of the pole terms in the parity-conserving transitions is evident. This can naturally explain the sizable branching ratio for Ξc0→Λcπ− as recently reported by LHCb. The same mechanism predicts a large branching ratio for Ξc+→Λcπ0. In contrast, the decays of Ξb will only go through the parity-violating processes because of the HQS. In addition, the branching ratios of the Ξc+→Λcπ0 and Ξb0→Λbπ0 processes are also predicted for the further experimental measurement.

Production of light 𝚵-hypernuclei, 𝚵7H

A light Ξ hypernucleus, Ξ7H, is expected to be bound. Furthermore, it is pointed out that Ξ7H will decay into ΛΛ5H with a large branching ratio. We plan to study the 7Li(K−, K+) reaction to investigate the Ξ7H system and to evaluate the experimental feasibility to perform decay pion spectroscopy of ΛΛ5H in future.

Search for charginos and neutralinos in final states with two boosted hadronically decaying bosons and missing transverse momentum in pp collisions at s=13 TeV with the ATLAS detector

A search for charginos and neutralinos at the Large Hadron Collider is reported using fully hadronic final states and missing transverse momentum. Pair-produced charginos or neutralinos are explored, each decaying into a high-$p_{\text{T}}$ Standard Model weak boson. Fully-hadronic final states are studied to exploit the advantage of the large branching ratio, and the efficient background rejection by identifying the high-$p_{\text{T}}$ bosons using large-radius jets and jet substructure information. An integrated luminosity of 139 fb$^{-1}$ of proton-proton collision data collected by the ATLAS detector at a center-of-mass energy of 13 TeV is used. No significant excess is found beyond the Standard Model expectation. The 95% confidence level exclusion limits are set on wino or higgsino production with varying assumptions in the decay branching ratios and the type of the lightest supersymmetric particle. A wino (higgsino) mass up to 1060 (900) GeV is excluded when the lightest SUSY particle mass is below 400 (240) GeV and the mass splitting is larger than 400 (450) GeV. The sensitivity to high-mass wino and higgsino is significantly extended compared with the previous LHC searches using the other final states.

Effect of K0−K¯0 mixing on CP and CPT violations in Bc±→B±KS,L0 decays

The large data sample of the $B_c$ meson collected at the LHC experiment and the HL-LHC experiment provides us the opportunity to study the $B_c$ decays and the related physics. In this paper, we investigate the effect of $K^0-\bar{K}^0$ mixing on the the branching ratios, CP violations and CPT violations in the $B_{c}^{\pm}\rightarrow B^{\pm} K_{S,L}^{0}$ decays. We find that some of the $B_c^{\pm}\rightarrow B^{\pm} K_{S,L}^0\rightarrow f_{B^{\pm}} f_{K_{S,L}^0}$ decay chains have large branching ratios, whose maximum value can exceed the order of $10^{-6}$, the minimum number of $B_c^\pm$ events times efficiency for observing the decays at three standard deviations (3$\sigma$) level is about $ 10^6$. We study the CP asymmetries in the $B_c^{\pm}\rightarrow B^{\pm} K_{S,L}^0$ decays and find that the CP asymmetries can exceed the order of $10^{-3}$, which are dominated by $K^0-\bar{K}^0$ mixing. We give the most promising processes to observe the CP violations and the ranges of the numbers of $B_c^\pm$ events-times-efficiency needed to observe the CP asymmetries at a significance of 3$\sigma$ in these decays. We investigate the possibility to constraint the CPT violation parameter $z$ in the $B_c^{\pm}\rightarrow B^{\pm} K_{S,L}^0\rightarrow f_{B^{\pm}} f_{K_{S,L}^0}$ decays and give the most promising processes to constraint the parameter $z$.

Study of C parity violating and strangeness changing J/ψ → PP weak decays * *Supported by the National Natural Science Foundation of China (11705047, 11981240403, U1632109, 11547014, 11875122), the Program for Innovative Research Team in University of Henan Province (19IRTSTHN018), the Excellent Youth Foundation of Henan Province (212300410010) and the Chinese Academy of Sciences Large-Scale Scientific Facility Program (1G2017IHEPKFYJ01)

Although weak decays are rare, they are possible within the standard model of elementary particles. Inspired by the potential prospects of the future intensity frontier, the C parity violating , decays and the strangeness changing , decays are studied via the perturbative QCD approach. It is determined that the decays have relatively large branching ratios, approximately on the order of , which might be within the measurement capability and sensitivity of the future STCF experiment.

CP violation in non-leptonic B_c decays to excited final states

We study the CP violation in two-body nonleptonic decays of B_c meson. We concentrate on the decay channels which contain at least one excited heavy meson in the final states. Specifically, the following channels are considered: B_crightarrow c{bar{c}}(2S, 2P)+{bar{c}}q(1S, 1P), B_crightarrow c{bar{c}}(1S)+{bar{c}}q(2S, 2P), B_crightarrow c{bar{c}}(1P)+{bar{c}}q(2S), B_crightarrow c{bar{c}}(1D)+{bar{c}}q(1S, 1P), and B_crightarrow c{bar{c}}(3S)+{bar{c}}q(1S). The improved Bethe-Salpeter method is applied to calculate the hadronic transition matrix element. Our results show that some decay modes have large branching ratios, which is of the order of 10^{-3}. The CP violation effect in B_c rightarrow eta _c(1S)+D(2S), B_c rightarrow eta _c(1S)+D_0^{*}(2P), and B_c rightarrow J/psi +D^{*}(2S) are most likely to be found. If the detection precision of the CP asymmetry in such channels can reach the 3sigma level, at least 10^7B_c events are needed.

Insights into the Microstructures and Energy Levels of Pr3+-Doped YAlO3 Scintillating Crystals.

Trivalent praseodymium (Pr3+)-doped materials have been extensively used in high-resolution laser spectroscopy, owing to their outstanding conversion efficiencies of plentiful transitions in the visible laser region. However, to clarify the microstructure and energy transfer mechanism of Pr3+-doped host crystals is a challenging topic. In this work, the stable structures of Pr3+-doped yttrium orthoaluminate (YAlO3) have been widely searched based on the CALYPSO method. A novel monoclinic structure with the Pm group symmetry is successfully identified. The Pr3+ impurity can precisely occupy the Y3+ position and get incorporated into the YAlO3 (YAP) host crystal with a Pr3+ concentration of 6.25%. The result of the electronic band structure reveals a 3.62 eV band gap, which suggests a semiconductor character of YAP:Pr. Using our developed well-established parametrization matrix diagonalization (WEPMD) method, we have systematically analyzed the energy level scheme and proposed a set of newly improved parameters. Additionally, the energy transfer mechanism of YAP:Pr is clarified by deciphering the numerical electric dipole and magnetic dipole transitions. The popular red emission at 653 nm is assigned to the transition 3P0 → 3F2, while the transition 3P0 → 3H4 with a large branching ratio is predicted to be a good laser channel. Many promising emission lines for laser actions are also obtained in the visible light region. Our results not only provide important insights into the energy transfer mechanisms of rare-earth ion-doped materials but also pave the way for the implementation of new types of laser devices.

Baryonic Higgs and dark matter

We discuss the correlation between dark matter and Higgs decays in gauge theories where the dark matter is predicted from anomaly cancellation. In these theories, the Higgs responsible for the breaking of the gauge symmetry generates the mass for the dark matter candidate. We investigate the Higgs decays in the minimal gauge theory for Baryon number. After imposing the dark matter density and direct detection constraints, we find that the new Higgs can have a large branching ratio into two photons or into dark matter. Furthermore, we discuss the production channels and the unique signatures at the Large Hadron Collider.