The X(3872)is theoretically predicted to have a spin-0 partner state denoted as X_(0).Assuming the X_(0)as a molecular bound state,we calculate the decay widths of X_(0)→VV and X_(0)→PP(V and P stand for light vecto...The X(3872)is theoretically predicted to have a spin-0 partner state denoted as X_(0).Assuming the X_(0)as a molecular bound state,we calculate the decay widths of X_(0)→VV and X_(0)→PP(V and P stand for light vector and pseudoscalar mesons,respectively)via intermediate charmed meson loops.Three different configurations of the X_(0),i.e.,pure neutral components(θ=0),isospin singlet(θ=π/4),and pure charged components(θ=π/2),are investigated.Within a commonly accepted range of the model parameterα,the predicted decay widths of X_(0)→VV are on the order of a few hundred keV,while the decay widths of X_(0)→PP can reach several MeV.The X_(0)→ρρandππhave larger decay rates.The relative width ratios between the channels are nearly model-independent.Moreover,among those channels only with isovector or isoscalar mesons,the relevant ratios are also independent of the phase angle.The predicted ratios are helpful for searching the X_(0)in the future experiments at BESIII and Belle II.展开更多
By employing the perturbative QCD （pQCD） factorization approach, we calculate some important next- to-leading-order （NLO） contributions to the two-body charmless hadronic decays B^＋ →ρ^＋η（＇） and B^0 → ρ^...By employing the perturbative QCD （pQCD） factorization approach, we calculate some important next- to-leading-order （NLO） contributions to the two-body charmless hadronic decays B^＋ →ρ^＋η（＇） and B^0 → ρ^0（ω, φ）η（＇）, induced by the vertex QCD corrections, the quark-loops as well as the chromo-magnetic penguins. From the numerical results and phenomenological analysis we find that （a） for B^± → ρ^±η（＇） （B^0 → ρ^0（ω, φ）η（＇）decays, the partial NLO contributions to branching ratios are small （large） in magnitude; and （b） the pQCD predictions for ACP^dir（B^± → ρ^±η（＇）） are consistent with the data, while the predicted .ACP（B^0 → ρ^0（ω）η（＇）） are generally large in magnitude and could be tested by the forthcoming LHCb experiments.展开更多
The phenomenological non-relativistic quark model （NRQM） has been employed to obtain the masses of bottomonium states. In the frame work of NRQM an exhaustive study of radiative and leptonic decays has been made. Th...The phenomenological non-relativistic quark model （NRQM） has been employed to obtain the masses of bottomonium states. In the frame work of NRQM an exhaustive study of radiative and leptonic decays has been made. The Hamiltonian used in the investigation has kinetic energy, confinement potentiM and one gluon exchange potential （OGEP）. An overall agreement is obtained with the experimental masses and decay widths.展开更多
Warm and cold phases of El Nino–Southern Oscillation (ENSO) exhibit a significant asymmetry in their decay speed. To explore the physical mechanism responsible for this asymmetric decay speed, the asymmetric features...Warm and cold phases of El Nino–Southern Oscillation (ENSO) exhibit a significant asymmetry in their decay speed. To explore the physical mechanism responsible for this asymmetric decay speed, the asymmetric features of anomalous sea surface temperature (SST) and atmospheric circulation over the tropical Western Pacific (WP) in El Nino and La Nina mature-to-decay phases are analyzed. It is found that the interannual standard deviations of outgoing longwave radiation and 850 hPa zonal wind anomalies over the equatorial WP during El Nino (La Nina) mature-to-decay phases are much stronger (weaker) than the intraseasonal standard deviations. It seems that the weakened (enhanced) intraseasonal oscillation during El Nino (La Nina) tends to favor a stronger (weaker) interannual variation of the atmospheric wind, resulting in asymmetric equatorial WP zonal wind anomalies in El Nino and La Nina decay phases. Numerical experiments demonstrate that such asymmetric zonal wind stress anomalies during El Nino and La Nina decay phases can lead to an asymmetric decay speed of SST anomalies in the central-eastern equatorial Pacific through stimulating di erent equatorial Kelvin waves. The largest negative anomaly over the Nino3 region caused by the zonal wind stress anomalies during El Nino can be threefold greater than the positive Nino3 SSTA anomalies during La Nina, indicating that the stronger zonal wind stress anomalies over the equatorial WP play an important role in the faster decay speed during El Nino.展开更多
Superstrong static electric fields could deform Coulomb barriers between α clusters and daughter nuclei,and bring up the possibility of speeding up α decays. We adopt a simplified model for the spherical α emitter^...Superstrong static electric fields could deform Coulomb barriers between α clusters and daughter nuclei,and bring up the possibility of speeding up α decays. We adopt a simplified model for the spherical α emitter^(212)Po and study its responses to superstrong static electric fields. We find that superstrong electric fields with field strengths|E|～0.1 MV/fm could turn the angular distribution of α emissions from isotropic to strongly anisotropic, and speed upα decays by more than one order of magnitude. We also study the influences of superstrong electric fields along the Po isotope chains, and discuss the implications of our studies on α decays in superstrong monochromatic laser fields. The study here might be helpful for future theoretical studies of α decay in realistic superstrong laser fields.展开更多
Considering the experimental constraints on the free parameters of the 331 model with a leptonic sector consistent of five triplets, we investigate the lepton flavor violation(LFV) tau decays τ→μM with M = P and V,...Considering the experimental constraints on the free parameters of the 331 model with a leptonic sector consistent of five triplets, we investigate the lepton flavor violation(LFV) tau decays τ→μM with M = P and V,where P and V denote a pseudoscalar meson(π, η or η′) and a vector meson(ρ0, ω or φ), respectively. We find that the contributions of the 331 model to the LFV decays τ→μM mainly come from the new neutral gauge boson Z′. The 331 model considered in this paper can not make the values of the branching ratio Br(τ→μM) approach the corresponding experimental upper limits.展开更多
Majorana zero modes in the hybrid semiconductor-superconductornanowire is one of the promising candidates for topologicalquantum computing. Recently, in nanowires with a superconductingisland, the signature of Majoran...Majorana zero modes in the hybrid semiconductor-superconductornanowire is one of the promising candidates for topologicalquantum computing. Recently, in nanowires with a superconductingisland, the signature of Majorana zero modescan be revealed as a subgap state whose energy oscillatesaround zero in magnetic field. This oscillation was interpretedas overlapping Majoranas. However, the oscillation amplitudeeither dies away after an overshoot or decays, sharply oppositeto the theoretically predicted enhanced oscillations for Majoranabound states, as the magnetic field increases. Several theoreticalstudies have tried to address this discrepancy, but arepartially successful. This discrepancy has raised the concernson the conclusive identification of Majorana bound states, andhas even endangered the scheme of Majorana qubits basedon the nanowires.展开更多
In this article, we calculate the B＊→ηc form-factors with the three-point QCD sum rules, then study the semileptonic decays B＊→ηclυl. The tiny decay widths may be observed experimentally in the future at the LH...In this article, we calculate the B＊→ηc form-factors with the three-point QCD sum rules, then study the semileptonic decays B＊→ηclυl. The tiny decay widths may be observed experimentally in the future at the LHCb, while the B＊→ηc form-factors can be taken as basic input parameters in other phenomenologieal analysis.展开更多
Amplitudes for φ（2S） sequential decays into 2（π^＋π^-）pp^-γ via XCJ are constructed in effective coupling scheme. A Mote-Carlo simulation is carried out to study angular distributions of the decayed particles ...Amplitudes for φ（2S） sequential decays into 2（π^＋π^-）pp^-γ via XCJ are constructed in effective coupling scheme. A Mote-Carlo simulation is carried out to study angular distributions of the decayed particles in laboratory system. The results can be taken as a reference for measuring the decay of XCJ into at BESⅡ/BEPC in the near future.展开更多
Motivated by the recently updated experimental measurement on Bd→μ^＋μ^- and B^-→π^-μ＋μ^- decays by CDF and Belle collaborations, we revisit these decays, as well as B^-→ρ^-μ^＋μ^- decay, within the Standa...Motivated by the recently updated experimental measurement on Bd→μ^＋μ^- and B^-→π^-μ＋μ^- decays by CDF and Belle collaborations, we revisit these decays, as well as B^-→ρ^-μ^＋μ^- decay, within the Standard Model, and evaluate the effects of a family non-universal Z＇ boson. Under the constraint from β（B- → π^-μ＋μ^-）, we find the ranges of the Z＇ couplings SLRμμ 〈 -5.2 × 10^-2 or Dμμ^LR 〈 -8.1 × 10^-2 are excluded. Within the allowed Z＇ parameters spaces, comparing with the SM predictions, we find that B（Bd→μ^＋μ^-）, B（B^-→π^-μ＋μ^-）, and B（B^-→ρ^-μ＋μ^-） could be enhanced by a factor about 226%, 245%, and 254%, respectively, by Z＇ contributions. However, they are hardly to be reduced. Furthermore, the zero crossing in the normalized forward-backward asymmetry spectrum of B^-→ρ^-μ＋μ^- decay at low dimuon mass always exists.展开更多
In this article, we calculate the branching ratios of B→K0^＊ （1430）K decays by employing the pertur-bative QCD （pQCD） approach at leading order. We perform the evaluations in the two scenarios for the scalar mes...In this article, we calculate the branching ratios of B→K0^＊ （1430）K decays by employing the pertur-bative QCD （pQCD） approach at leading order. We perform the evaluations in the two scenarios for the scalar meson spectrum. We find that （i） The leading order pQCD predictions for the branching ratio Br（B^＋→K^＋K0^＊（1430）^0）are in good agreement with the experimental upper limit in both scenarios, while the pQCD predictions for other considered B→K0^＊（1430）K decay modes are also presented and will be tested by the LHC experiments; （ii） The annihilation contributions play an important role in these considered decays, for B^0→K0^＊（1430）^±K^± decays,for example,which are found to be （1-4）×10^-6.展开更多
In the framework of the heavy quark effective theory, the leading order Isgur-Wise functions relevant to semileptonie decays of the orbitally P-wave excited Bs meson states Bs＊, including the newly found narrow Bs1 ...In the framework of the heavy quark effective theory, the leading order Isgur-Wise functions relevant to semileptonie decays of the orbitally P-wave excited Bs meson states Bs＊, including the newly found narrow Bs1 （5830） andBs2（5840） states, into the （Ds1（2536）, Ds2（2573）） doublet are calculated from QCD sum rules. With these universal form factors, the decay rates and branching ratios are also estimated.展开更多
We study the CP-averaged branching fractions and the CP-violating asymmetries in the pure annihilation decays of B^(s)_(0)→a^(+)_(0)a^(−)_(0)and B^(0)_(d)→K^(∗+)_(0)K^(∗−)_(0),where a_(0)[K^(∗)_(0)]denotes the scala...We study the CP-averaged branching fractions and the CP-violating asymmetries in the pure annihilation decays of B^(s)_(0)→a^(+)_(0)a^(−)_(0)and B^(0)_(d)→K^(∗+)_(0)K^(∗−)_(0),where a_(0)[K^(∗)_(0)]denotes the scalar a_(0)(980)and a_(0)(1450)[K^(∗)_(0)(800)(orκ)and K^(∗)_(0)(1430)],with the perturbative QCD factorization approach under the assumption of two-quark structure for the a_(0)and K^(∗)_(0)states.The numerical results show that the branching ratios of the B^(0)_(d)→K^(∗+)_(0)K^(∗−)_(0)decays are in the order of 10^(−6),while the decay rates of the B^(s)_(0)→a^(+)_(0)a^(−)_(0)modes are in the order of 10−5.In light of the measured modes with the same quark components in the pseudoscalar sector,namely,B^(0)_(d)→K^(+)k_(-)and B^(0)_(s)→π^(+)π_(−),the predictions for the considered decay modes in this work are expected to be measured at the Large Hadron Collider beauty and/or Belle-Ⅱexperiments in the(near)future.Meanwhile,it is of great interest to find that the twist-3 distribution amplitudesφ^(S)andφ^(T)with inclusion of the Gegenbauer polynomials for the scalar a_(0)(1450)and K^(∗)_(0)(1430)states in scenario 2 contribute slightly to the branching ratios while significantly to the CP violations in the B^(0)_(d)→K^(∗)_(0)(1430)+K^(∗)_(0)(1430)−and B^(0)_(s)→a_(0)(1450)+a_(0)(1450)−decays,which indicates that,compared to the asymptoticφ^(S)andφ^(T),these Gegenbauer polynomials could change the strong phases evidently in these pure annihilation decay channels.These predictions await for the future confirmation experimentally,which could further provide useful information to help explore the inner structure of the scalars and shed light on the annihilation decay mechanism.展开更多
To explain the anomALously large decay rate of ∑＋→p＋μ＋μ-, it was proposed that a new mechanism where a light CP-odd pseudoscaJar boson of mAo = 214.3 MeV makes a crucial contribution. Later, some authors have s...To explain the anomALously large decay rate of ∑＋→p＋μ＋μ-, it was proposed that a new mechanism where a light CP-odd pseudoscaJar boson of mAo = 214.3 MeV makes a crucial contribution. Later, some authors have studied the transition π0→e＋e- and γ→γA10 in terms of the same mechanism and their result indicates that with the suggested mass one cannot fit the data. This discrepancy might be caused by experimental error of ∑＋→p＋μ＋μ- because there were only a few events. Whether the mechanism is a reasonable one motivates us to investigate the transitions π0→e＋e-;η（η′）→μ＋μ-;ηc→μ＋μ-;ηb→τ＋τ- within the same framework. It is noted that for π0→ e＋ e-, the standard model （SM） prediction is smaller than the data, whereas the experimental central value of η→μ＋μ- is also above the SM prediction. It means that there should be extra contributions from other mechanisms and the contribution of A may be a possible one. Theoretically calculating the branching ratios of the concerned modes, we would cheek if we can obtain a univers mass for A10 which reconcile the theoretical predictions and data for all the modes. Unfortunately, we find that it is impossible conclude that the phenomenology does not favor such a to have such a mass with the same coupling｜gt｜. Therefore we light A10, even though a small window is still open.展开更多
Axion-like particles（ALPs）are often defined as relatively light pseudoscalar particles and appear in many extensions of the Standard Model.Taking into account constraints on the free parameters from existing searche...Axion-like particles（ALPs）are often defined as relatively light pseudoscalar particles and appear in many extensions of the Standard Model.Taking into account constraints on the free parameters from existing searches and explaining the g-2 deviation,we consider the contributions of ALPs with mass in the range of 1.5GeV展开更多
To solve the/a problem of the Minimal Supersymmetric Standard Model （MSSM）, a single field S is added to build the Next Minimal Supersymmetric Standard Model （NMSSM）. Vacuum enlarged with non-zero vevs of the neut...To solve the/a problem of the Minimal Supersymmetric Standard Model （MSSM）, a single field S is added to build the Next Minimal Supersymmetric Standard Model （NMSSM）. Vacuum enlarged with non-zero vevs of the neutral-even CP is the combination of Hu, Hd and S. In the NMSSM, the Higgs sector is increased to 7 （compared with 5 hogs in the MSSM）, including three Higgs-which are the even-CP hi,2,3 （mh1〈 mh2〈 mh3）, two Higgs-which are odd-CP a1,2 （ma1 〈 ma2） and a couple of charged Higgs H^±. The decays Higgs into Higgs is one of the remarkable new points of the NMSSM. In this paper, we study the decays H^± into W^± and at. The decay width is calculated to one loop vertex correction. The numerical results are also described together with evaluations.展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.12475081 and 12105153)the Natural Science Foundation of Shandong Province(Grant Nos.ZR2021MA082 and ZR2022ZD26)Taishan Scholar Project of Shandong Province(Grant No.tsqn202103062).
文摘The X(3872)is theoretically predicted to have a spin-0 partner state denoted as X_(0).Assuming the X_(0)as a molecular bound state,we calculate the decay widths of X_(0)→VV and X_(0)→PP(V and P stand for light vector and pseudoscalar mesons,respectively)via intermediate charmed meson loops.Three different configurations of the X_(0),i.e.,pure neutral components(θ=0),isospin singlet(θ=π/4),and pure charged components(θ=π/2),are investigated.Within a commonly accepted range of the model parameterα,the predicted decay widths of X_(0)→VV are on the order of a few hundred keV,while the decay widths of X_(0)→PP can reach several MeV.The X_(0)→ρρandππhave larger decay rates.The relative width ratios between the channels are nearly model-independent.Moreover,among those channels only with isovector or isoscalar mesons,the relevant ratios are also independent of the phase angle.The predicted ratios are helpful for searching the X_(0)in the future experiments at BESIII and Belle II.
基金Supported by the National Natural Science Foundation of China under Grant No.10575052,10605012,and 10735080
文摘By employing the perturbative QCD （pQCD） factorization approach, we calculate some important next- to-leading-order （NLO） contributions to the two-body charmless hadronic decays B^＋ →ρ^＋η（＇） and B^0 → ρ^0（ω, φ）η（＇）, induced by the vertex QCD corrections, the quark-loops as well as the chromo-magnetic penguins. From the numerical results and phenomenological analysis we find that （a） for B^± → ρ^±η（＇） （B^0 → ρ^0（ω, φ）η（＇）decays, the partial NLO contributions to branching ratios are small （large） in magnitude; and （b） the pQCD predictions for ACP^dir（B^± → ρ^±η（＇）） are consistent with the data, while the predicted .ACP（B^0 → ρ^0（ω）η（＇）） are generally large in magnitude and could be tested by the forthcoming LHCb experiments.
文摘The phenomenological non-relativistic quark model （NRQM） has been employed to obtain the masses of bottomonium states. In the frame work of NRQM an exhaustive study of radiative and leptonic decays has been made. The Hamiltonian used in the investigation has kinetic energy, confinement potentiM and one gluon exchange potential （OGEP）. An overall agreement is obtained with the experimental masses and decay widths.
基金supported by the China National 973 Project (Grant No.2015CB453203)the National Key R&D Program of China (Grant No.2016YFA0600602)the National Natural Science Foundation of China (Grant No.41661144017)
文摘Warm and cold phases of El Nino–Southern Oscillation (ENSO) exhibit a significant asymmetry in their decay speed. To explore the physical mechanism responsible for this asymmetric decay speed, the asymmetric features of anomalous sea surface temperature (SST) and atmospheric circulation over the tropical Western Pacific (WP) in El Nino and La Nina mature-to-decay phases are analyzed. It is found that the interannual standard deviations of outgoing longwave radiation and 850 hPa zonal wind anomalies over the equatorial WP during El Nino (La Nina) mature-to-decay phases are much stronger (weaker) than the intraseasonal standard deviations. It seems that the weakened (enhanced) intraseasonal oscillation during El Nino (La Nina) tends to favor a stronger (weaker) interannual variation of the atmospheric wind, resulting in asymmetric equatorial WP zonal wind anomalies in El Nino and La Nina decay phases. Numerical experiments demonstrate that such asymmetric zonal wind stress anomalies during El Nino and La Nina decay phases can lead to an asymmetric decay speed of SST anomalies in the central-eastern equatorial Pacific through stimulating di erent equatorial Kelvin waves. The largest negative anomaly over the Nino3 region caused by the zonal wind stress anomalies during El Nino can be threefold greater than the positive Nino3 SSTA anomalies during La Nina, indicating that the stronger zonal wind stress anomalies over the equatorial WP play an important role in the faster decay speed during El Nino.
基金Supported by the National Natural Science Foundation of China under Grant Nos.11535004,11761161001,11375086,11120101005,11175085 and 11235001the National Key R&D Program of China under Grant No.2018YFA0404403+1 种基金the National Major State Basic Research and Development of China,under Grant No.2016YFE0129300the Science and Technology Development Fund of Macao under Grant No.008/2017/AFJ
文摘Superstrong static electric fields could deform Coulomb barriers between α clusters and daughter nuclei,and bring up the possibility of speeding up α decays. We adopt a simplified model for the spherical α emitter^(212)Po and study its responses to superstrong static electric fields. We find that superstrong electric fields with field strengths|E|～0.1 MV/fm could turn the angular distribution of α emissions from isotropic to strongly anisotropic, and speed upα decays by more than one order of magnitude. We also study the influences of superstrong electric fields along the Po isotope chains, and discuss the implications of our studies on α decays in superstrong monochromatic laser fields. The study here might be helpful for future theoretical studies of α decay in realistic superstrong laser fields.
基金Supported by the National Natural Science Foundation of China under Grant No.11275088the Natural Science Foundation of the Liaoning Scientific Committee under Grant No.201102114Foundation of Liaoning Educational Committee under Grant No.LT2011015
文摘Considering the experimental constraints on the free parameters of the 331 model with a leptonic sector consistent of five triplets, we investigate the lepton flavor violation(LFV) tau decays τ→μM with M = P and V,where P and V denote a pseudoscalar meson(π, η or η′) and a vector meson(ρ0, ω or φ), respectively. We find that the contributions of the 331 model to the LFV decays τ→μM mainly come from the new neutral gauge boson Z′. The 331 model considered in this paper can not make the values of the branching ratio Br(τ→μM) approach the corresponding experimental upper limits.
文摘Majorana zero modes in the hybrid semiconductor-superconductornanowire is one of the promising candidates for topologicalquantum computing. Recently, in nanowires with a superconductingisland, the signature of Majorana zero modescan be revealed as a subgap state whose energy oscillatesaround zero in magnetic field. This oscillation was interpretedas overlapping Majoranas. However, the oscillation amplitudeeither dies away after an overshoot or decays, sharply oppositeto the theoretically predicted enhanced oscillations for Majoranabound states, as the magnetic field increases. Several theoreticalstudies have tried to address this discrepancy, but arepartially successful. This discrepancy has raised the concernson the conclusive identification of Majorana bound states, andhas even endangered the scheme of Majorana qubits basedon the nanowires.
基金Supported by National Natural Science Foundation under Grant Nos.11075053,11375063the Fundamental Research Funds for the Central Universities
文摘In this article, we calculate the B＊→ηc form-factors with the three-point QCD sum rules, then study the semileptonic decays B＊→ηclυl. The tiny decay widths may be observed experimentally in the future at the LHCb, while the B＊→ηc form-factors can be taken as basic input parameters in other phenomenologieal analysis.
基金the National Natural Science Foundation of China under
文摘Amplitudes for φ（2S） sequential decays into 2（π^＋π^-）pp^-γ via XCJ are constructed in effective coupling scheme. A Mote-Carlo simulation is carried out to study angular distributions of the decayed particles in laboratory system. The results can be taken as a reference for measuring the decay of XCJ into at BESⅡ/BEPC in the near future.
基金Supported by the National Natural Science Foundation under Grant Nos. 11105043 and 11075059Research Fund for the Doctoral Program of Higher Education of China under Grant No. 20114104120002Startup Foundation for Doctor of Henan Normal University under Grant No. 1006
文摘Motivated by the recently updated experimental measurement on Bd→μ^＋μ^- and B^-→π^-μ＋μ^- decays by CDF and Belle collaborations, we revisit these decays, as well as B^-→ρ^-μ^＋μ^- decay, within the Standard Model, and evaluate the effects of a family non-universal Z＇ boson. Under the constraint from β（B- → π^-μ＋μ^-）, we find the ranges of the Z＇ couplings SLRμμ 〈 -5.2 × 10^-2 or Dμμ^LR 〈 -8.1 × 10^-2 are excluded. Within the allowed Z＇ parameters spaces, comparing with the SM predictions, we find that B（Bd→μ^＋μ^-）, B（B^-→π^-μ＋μ^-）, and B（B^-→ρ^-μ＋μ^-） could be enhanced by a factor about 226%, 245%, and 254%, respectively, by Z＇ contributions. However, they are hardly to be reduced. Furthermore, the zero crossing in the normalized forward-backward asymmetry spectrum of B^-→ρ^-μ＋μ^- decay at low dimuon mass always exists.
基金Supported by the National Natural Science Foundation of China under Grant Nos. 10575052, 10605012, and 10735080
文摘In this article, we calculate the branching ratios of B→K0^＊ （1430）K decays by employing the pertur-bative QCD （pQCD） approach at leading order. We perform the evaluations in the two scenarios for the scalar meson spectrum. We find that （i） The leading order pQCD predictions for the branching ratio Br（B^＋→K^＋K0^＊（1430）^0）are in good agreement with the experimental upper limit in both scenarios, while the pQCD predictions for other considered B→K0^＊（1430）K decay modes are also presented and will be tested by the LHC experiments; （ii） The annihilation contributions play an important role in these considered decays, for B^0→K0^＊（1430）^±K^± decays,for example,which are found to be （1-4）×10^-6.
基金Supported by the National Natural Science Foundation of China under Grant No. 10975184
文摘In the framework of the heavy quark effective theory, the leading order Isgur-Wise functions relevant to semileptonie decays of the orbitally P-wave excited Bs meson states Bs＊, including the newly found narrow Bs1 （5830） andBs2（5840） states, into the （Ds1（2536）, Ds2（2573）） doublet are calculated from QCD sum rules. With these universal form factors, the decay rates and branching ratios are also estimated.
基金supported in part by the National Natural Science Foundation of China under Grant Nos.11765012 and 11205072by the Research Fund of Jiangsu Normal University(No.HB2016004)supported by the Undergraduate Research&Practice Innovation Program of Jiangsu Province(No.201810320103Z)。
文摘We study the CP-averaged branching fractions and the CP-violating asymmetries in the pure annihilation decays of B^(s)_(0)→a^(+)_(0)a^(−)_(0)and B^(0)_(d)→K^(∗+)_(0)K^(∗−)_(0),where a_(0)[K^(∗)_(0)]denotes the scalar a_(0)(980)and a_(0)(1450)[K^(∗)_(0)(800)(orκ)and K^(∗)_(0)(1430)],with the perturbative QCD factorization approach under the assumption of two-quark structure for the a_(0)and K^(∗)_(0)states.The numerical results show that the branching ratios of the B^(0)_(d)→K^(∗+)_(0)K^(∗−)_(0)decays are in the order of 10^(−6),while the decay rates of the B^(s)_(0)→a^(+)_(0)a^(−)_(0)modes are in the order of 10−5.In light of the measured modes with the same quark components in the pseudoscalar sector,namely,B^(0)_(d)→K^(+)k_(-)and B^(0)_(s)→π^(+)π_(−),the predictions for the considered decay modes in this work are expected to be measured at the Large Hadron Collider beauty and/or Belle-Ⅱexperiments in the(near)future.Meanwhile,it is of great interest to find that the twist-3 distribution amplitudesφ^(S)andφ^(T)with inclusion of the Gegenbauer polynomials for the scalar a_(0)(1450)and K^(∗)_(0)(1430)states in scenario 2 contribute slightly to the branching ratios while significantly to the CP violations in the B^(0)_(d)→K^(∗)_(0)(1430)+K^(∗)_(0)(1430)−and B^(0)_(s)→a_(0)(1450)+a_(0)(1450)−decays,which indicates that,compared to the asymptoticφ^(S)andφ^(T),these Gegenbauer polynomials could change the strong phases evidently in these pure annihilation decay channels.These predictions await for the future confirmation experimentally,which could further provide useful information to help explore the inner structure of the scalars and shed light on the annihilation decay mechanism.
基金Supported by the National Natural Science Foundation of China under Grant Nos.11075079and11005079the Special Grant for the Ph.D.Program of Ministry of Eduction of China No.20100032120065
文摘To explain the anomALously large decay rate of ∑＋→p＋μ＋μ-, it was proposed that a new mechanism where a light CP-odd pseudoscaJar boson of mAo = 214.3 MeV makes a crucial contribution. Later, some authors have studied the transition π0→e＋e- and γ→γA10 in terms of the same mechanism and their result indicates that with the suggested mass one cannot fit the data. This discrepancy might be caused by experimental error of ∑＋→p＋μ＋μ- because there were only a few events. Whether the mechanism is a reasonable one motivates us to investigate the transitions π0→e＋e-;η（η′）→μ＋μ-;ηc→μ＋μ-;ηb→τ＋τ- within the same framework. It is noted that for π0→ e＋ e-, the standard model （SM） prediction is smaller than the data, whereas the experimental central value of η→μ＋μ- is also above the SM prediction. It means that there should be extra contributions from other mechanisms and the contribution of A may be a possible one. Theoretically calculating the branching ratios of the concerned modes, we would cheek if we can obtain a univers mass for A10 which reconcile the theoretical predictions and data for all the modes. Unfortunately, we find that it is impossible conclude that the phenomenology does not favor such a to have such a mass with the same coupling｜gt｜. Therefore we light A10, even though a small window is still open.
基金Supported by the National Natural Science Foundation of China under Grant Nos 11275088 and 11747318
文摘Axion-like particles（ALPs）are often defined as relatively light pseudoscalar particles and appear in many extensions of the Standard Model.Taking into account constraints on the free parameters from existing searches and explaining the g-2 deviation,we consider the contributions of ALPs with mass in the range of 1.5GeV
文摘To solve the/a problem of the Minimal Supersymmetric Standard Model （MSSM）, a single field S is added to build the Next Minimal Supersymmetric Standard Model （NMSSM）. Vacuum enlarged with non-zero vevs of the neutral-even CP is the combination of Hu, Hd and S. In the NMSSM, the Higgs sector is increased to 7 （compared with 5 hogs in the MSSM）, including three Higgs-which are the even-CP hi,2,3 （mh1〈 mh2〈 mh3）, two Higgs-which are odd-CP a1,2 （ma1 〈 ma2） and a couple of charged Higgs H^±. The decays Higgs into Higgs is one of the remarkable new points of the NMSSM. In this paper, we study the decays H^± into W^± and at. The decay width is calculated to one loop vertex correction. The numerical results are also described together with evaluations.
