Francesco Giacosa, Giuseppe Pagliara
We study the line shapes of radiative $ϕ$-decays involving virtual $f_{0}(980)$ and $a_{0}(980)$ mesons which decay, via derivative couplings, to $π^{0}π^{0}$ and $π^{0}η$ respectively. After developing the formalism for derivative interactions at one-loop level, we show that they can reproduce the measured peaked line shapes of $ϕ$-decays without including kaon loops.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
继续探索
We study the line shapes of radiative $ϕ$-decays with a direct coupling of the $ϕ$ meson to the $f_{0}(980)$ and $a_{0}(980)$ scalar mesons. The latter couple via derivative interactions to $π_0 π_0$ and $π_0 η$, respectively. Although the kaon-loop mechanism is usually regarded as the dominant mechanism in radiative $ϕ$ decays, here we test a different possibility: we set the kaon-loop to zero and we fit the theoretical curves to the data by retaining only the direct coupling. Remarkably, satisfactory fits can be achieved, mainly due to the effects of derivative interactions of scalar with ps…
I briefly review the theory status of exclusive rare radiative decays.
This talk discusses the theory of inclusive and exclusive radiative B decays, emphasizing the interplay of perturbative and non-perturbative effects and the importance CP and isospin asymmetries.
With usage of the Low theorem the general expression for amplitude of radiative kaon decay \k+ \to π+\pi0γis determined.
Quantitative signatures of glueballs in $J/ψ$ radiative decays are discussed. Further experimental and theoretical investigations are sugessted.
Muon pair production in exclusive radiative decays $χ_{cJ}\to J/ψμμ$, $χ_{bJ}\toΥμμ$ are considered. We present numerical values of the branching fractions and distributions over various kinematical variables.
We review semi-inclusive charmless B decays, focussing on threshold logarithmic resumming and on universality of QCD dynamics in radiative and semileptonic decays.
In this talk I review recent developments in the calculation of radiative corrections to $K, D, B$ meson decays and discuss their impact on precision phenomenology.
A current status report on radiative inclusive and exclusive B decays is presented.
The transition form factors responsible for the radiative $Σ_Q \to Λ_Q γ$ and $Ξ_Q^\prime \to Ξγ$ decays of the negative parity baryons are examined within light cone QCD sum rules. The decay widths of the radiative transitions are calculated using the obtained results of the form factors.
Using the recent measurement of the $Ξ^0 \to Λγ$ asymmetry as an input, we reanalyse nonleptonic and weak radiative hyperon decays in a single symmetry-based framework. In this framework the old S:P problem of nonleptonic decays is automatically resolved when the most important features of weak radiative decays are taken into account. Experimental data require that symmetry between the two types of hyperon decays be imposed at the level of currents, not fields. Previously established connections between hyperon decays and nuclear parity violation imply that the conflict, originally suggested b…
This talk discusses recent developments in the theory of inclusive radiative B decays, focusing mainly on non-perturbative aspects of B->Xs gamma.
We extend the approach of Dolgov and Zakharov to the axial anomaly to study polarized radiative decays. We analyse the pattern of mass singularity cancellation in the corresponding decay rates. We compare polarized and unpolarized cases. The cancellation of the infrared and collinear singularities is verified to all powers of the lepton mass for the $π^+$ and $Z^0$ polarized radiative decays.
One-loop QED corrections to the differential width of radiative muon decay are considered. Results can be used to analyze high statistics data of modern and future experiments.
We discuss a connection between axial anomaly and polarized radiative processes. By comparison with the corresponding unpolarized cases, we consider some physical outputs for the $π^+$ and $Z^0$ polarized radiative decays. We analyse in detail the pattern of mass singularity cancellation.
The radiative "B_c -> tau nu_tau gamma" decay is analyzed in the standard model. The branching ratio of this decay is calculated and the contributions of the Bremstrahlung and structure dependent parts are compared. It is shown that this decay can be detected at LHC.
We report on the status of a variety of radiative B decays studied by the CLEO detector with $9.7\times 10^6$ $B\bar{B}$ pairs.
The real time exponential decay laws for meta-stable charged particles are shown to require radiative corrections. The methods employed are well known to be valid for radiatively correcting Breit-Wigner line shapes. Radiative corrections contribute substantially to precision life time measurements of muons and pions when initially stopped in condensed matter.
Radiative muon and tau lepton decays are described within the model-independent approach with the help of generalized Michel parameters. The exact dependence on charged lepton masses is taken into account. The results are relevant for modern and future experiments on muon and tau lepton decays.
Minor (mainly numerical) corrections.
I review recent developments in rare and radiative kaon decays from the theory side, with emphasis on those modes that are actively analyzed by the experimental collaborations.
We consider the inclusive radiative decays quarkonium -> gamma + hadrons and examine the effects of soft QCD radiation on the photon energy spectrum near the endpoint.
We study the radiative decay into $γ$ and a baryon of the SU(3) decuplet of ten resonances that are dynamically generated from the interaction of vector mesons with baryons of the decuplet. We obtain quite different partial decay widths for the various resonances, and for different charge states of the same resonance, suggesting that the experimental investigation of these radiative decays should bring much information on the nature of these resonances.
For high precision measurements of K decays, the presence of radiated photons cannot be neglected. The Monte Carlo simulations must include the radiative corrections in order to compute the correct event counting and efficiency calculations. In this paper we briefly describe a method for simulating such decays.
Radiative muon decay in the kinematics similar to the neutrinoless decay $μ\to eγ$ is considered. Radiative corrections due to 1-loop virtual photons and emission of additional soft or hard photons are taken into account. Analytical expressions and numerical estimations are presented.
Weak radiative decays of beauty baryons into strange baryons, induced by the electroweak penguin, are estimated by using a quark model approach. Relations between formfactors in the semileptonic and in the weak radiative decays are derived within the heavy quark effective theory. The partial decay widths are found to be of the order of $10^{-15}{\rm MeV}$ for $Λ_b\rightarrowΛγ$ and $Ξ_b\rightarrowΞγ$ and of the oder of $10^{-13}{\rm MeV}$ for $Ω_b\rightarrowΩγ$. The $Ω_b$ radiative decay is thus expected at the sizable branching ratio of approximately $10^{-4}$.
Rare radiative leptonic decay $B\to l\bar ν_l γ$ is studied in the instantaneous Bethe-Salpeter approach. The results are compared to other relativistic quark model predictions.
This talk discusses recent developments in the theory of inclusive radiative B decays, focusing mainly on non-perturbative aspects of the CP asymmetry in B->Xs gamma.
In this article, we study the radiative decays among the charmonium states with the heavy quark effective theory, and make predictions for the ratios among the radiative decay widths of an special multiplet to another multiplet. The predictions can be confronted with the experimental data in the future and put additional constraints in identifying the $X$, $Y$, $Z$ charmonium-like mesons.
I give a short overview of what has been done in radiative and semileptonic Kaon decays in Chiral Perturbation Theory. This includes for semileptonic decays the work which has been done to order $p^6$ including preliminary results of isospin breaking to that order in $K_{\ell3}$. For the radiative decays I mainly present some results from recent work concerning $K_{\ell3γ}$.
In this work, the radiative Bc -> D*_s gamma decay is investigated in the framework of QCD sum rules. The transition form factors responsible for the decay are calculated. The branching ratio for this decay is estimated to be order of 10^-5 which can be measurable at LHC.
A status report on the theory of radiative rare $B$ decays in the standard model is presented, with focus on inclusive decays $B \rightarrow X_{(s,d)}\, γ$ and exclusive decays $B \rightarrow (K^\ast,ω,ρ) \, γ$. CP asymmetries are also briefly discussed.
Theory of charmless radiative B decays is reviewed. Existence of uncontrolled non-perturbative effects in the inclusive rate at O(alpha_s) is reminded.
In this article, we perform an systematic study of the radiative transitions among the bottomonium states based on the heavy quarkonium effective theory, and make predictions for the ratios among the radiative decay widths of a special multiplet to another multiplet. The predictions can be confronted with the experimental data in the future.
We show that the so-called parity-conserving amplitudes predicted in the a priori mixing scheme for non-leptonic and weak radiative decays of hyperons vanish in the strong-flavor symmetry limit.
The radiative decay of muon-neutrinos in matter with a scheme of mass-degenerate neutrinos could be the common origin of the appearance of anti-electron-neutrinos at LSND and the disappearance of muons-neutrinos at SuperKamiokande. With the decay probability fixed by the LSND signal, the deficit of atmospheric neutrinos can be satisfactorily reproduced.
A reanalysis of the radiative pion decay together with the calculation of the radiative corrections within chiral perturbation theory (CHPT) is performed. The amplitude of this decay contains an inner Bremsstrahlung contribution and a structure-dependent part that are both accessible in experiments. In order to obtain a reliable estimate of the hadronic contributions we combine the CHPT result with a large-N_C expansion and experimental data on other decays, which makes it possible to determine the occurring coupling constants.
We consider meson radiative decays within the framework of $U_0(1)\times U(1)\times SU(2)$ gauge symmetry. This approach is based on the linear sigma-model extended by the gauge and quark-meson interactions. Physical content and parameters of the model are discussed. Theoretical predictions for some radiative decays of vector mesons are in a good agreement with the experimental data.
Radiative decays of the $1^3S_1$ radial and $1^3D_1$ orbital excitations of the $ρ$, $ω$ and $ϕ$ are calculated in the quark model, using wave functions obtained variationally from the Hamiltonian with standard quark-model parameters. The larger radiative widths should be measurable at new high-intensity facilities being proposed, and in some cases may be measurable in data from existing experiments. The radiative decays are a strong discriminator between the $1^3S_1$ and $1^3D_1$ excitations, and can also be used to provide unique information about the decay products.
We present a concise theoretical overview of radiative and rare B decays mediated by flavour-changing neutral-current transitions of the type b->s(d)gamma and b->s(d)l+l-.
We discuss theoretical issues in radiative rare kaon decays. The interest is twofold: to extract useful short-distance information and understand the underlying dynamics. We emphasize channels where either we can understand non-perturbative aspects of QCD or there is a chance to test the Standard Model.
Recent advances in the theoretical description of radiative Upsilon decays are reviewed, including the calculation of next-to-leading order QCD corrections to the photon spectrum.
We address Standard Model predictions for flavor-changing radiative transitions of the pseudoscalar charm mesons. Short-distance contributions in $D$ radiative transitions are contrasted with those in B decays. A full analysis is presented of the $c\to u+γ$ electromagnetic penguin amplitude with QCD radiative corrections included. Given the importance of long-range effects for the charm sector, special attention is paid to such contributions as the vector dominance and pole amplitudes. A number of two-body final states in exclusive charm radiative decays is considered and the corresponding bra…
After a brief review of the puzzling light scalar meson sector of QCD, a brief summary will be given of a paper concerning radiative decays involving the light scalars. There, a simple vector meson dominance model is constructed in an initial attempt to relate a large number of the radiative decays involving a putative scalar nonet to each other. As an application it is illustrated why $a_0(980)-f_0(980)$ mixing is not expected to greatly alter the $f_0/a_0$ production ratio for radiative $ϕ$ decays.
Combining heavy quark effective theory and the chiral Lagrangian approach we investigate D meson radiative decays. First, we reanalyse $D^{*} \rightarrow D γ$ decays using heavy quark spin symmetry, chiral symmetry Lagrangian, but including also the light vector mesons. Then, we calculate branching ratios $D \rightarrow V γ$. We make some comments on the Cabbibo suppressed decays $D \to ρ/ ωγ$ and the branching ratios of $D \rightarrow P P γ$ decays.
The radiative decays $ B^{*} (D^{*})\rightarrow B(D) γ$ are investigated in the framework of light cone QCD sum rules. The transition amplitude and decay rates are estimated.It is shown that our results on branching ratios of D meson decays are in good agreement with the existing experimental data.
We investigate the radiative B_c -> rho^+ gamma and B_c -> K^{*+} gamma decays in the standard model. The transition form factors are calculated in the framework of the light cone QCD sum rules method. We estimate the branching ratios of the B_c -> rho^+ gamma and B_c -> K^{*+} gamma decays.
The radiative decays of heavy baryons and lowest three doublets of heavy mesons are studied with the light cone QCD sum rules in the leading order of heavy quark effective theory.
In radiative $β$ decay, $T$ violation can be studied through a spin-independent $T$-odd correlation. We consider contributions to this correlation by beyond the standard model (BSM) sources of $T$-violation, arising above the electroweak scale. At the same time such sources, parametrized by dimension-6 operators, can induce electric dipole moments (EDMs). As a consequence, the manifestations of the $T$-odd BSM physics in radiative $β$ decay and EDMs are not independent. Here we exploit this connection to show that current EDM bounds already strongly constrain the spin-independent $T$-odd corre…
In the framework of the local Nambu-Jona-Lasinio model the radiative decay widths of the scalar mesons $f_0(980)$ and $a_0(980)$ into $ργ$ and $ωγ$ are calculated. The contributions of the quark loops and the meson loops are taken into account. For the radiative decays of the scalar meson $f_0(980)$ the contribution of the meson loops plays the dominant role. On the other side for the radiative decays of the scalar meson $a_0(980)$ the main contribution is given by the quark loops.
The order - αradiative corrections to the differential decay rate of polarized orthopositronium are obtained. Their influences on the three photons coincidence rate as a function of positronium polarization is considered.
We review the status of theory and experiment of very rare and forbidden kaon decays. We then review the radiative non-leptonic decays, and the associated Dalitz pair modes. We pay particular attention to the study of long distance physics in radiative decays within the framework of chiral perturbation theory ($χ$PT). We discuss the experiments that will run in the near future and the modes that they will be able to study.
The radiative decays of the p-wave charmed heavy baryons to the ground state baryon states are studied in the framework of the light cone QCD sum rules method. Firstly, the transition form factors that describe these transitions are estimated, and then using these form factors the corresponding decay widths are calculated. A comparison of our results on the decay widths with those predicted by the other approaches existing in literature is performed.
B_s-meson double radiative decay $B \to γγ$ is investigated in frame of supersymmetric extension of the standard model. The branching ratio is calculated. It is shown that for light Higgs particle and heigh $\tanβ$ supersymmetric contribution into branching ratio is significunt large than standard model estimate.
We investigate to what extent DA$Φ$NE will be able to test the Standard Model in the confinement regime with radiative kaon decays. We concentrate on processes which can be detected at DA$Φ$NE and we review briefly those decays where only upper limits can be expected. The Standard Model predictions for these decays are analyzed in the framework of chiral perturbation theory.
We evaluate the complete spectrum of the Bc mesons, below the open flavor BD threshold, in a Bethe-Salpeter model. We make predictions for the radiative decay widths of the Bc excited states. We compare our results with those of other models.
Using a recent calculation of transition magnetic moments in the 1/N_c expansion and a calculation showing the suppression of E2/M1 by powers of N_c, we compute the widths for the radiative decays Sigma^* --> Sigma gamma, Sigma^* --> Lambda gamma, and Xi^* --> Xi gamma.
We evaluate the radiative decay into a pseudoscalar meson and a photon of the whole set of the axial-vector mesons dynamically generated from the vector-pseudoscalar meson ($VP$) interaction. We take into account tree level and loop diagrams coming from the axial-vector decay into a vector and a pseudoscalar meson. We find a large span for the values of the radiative widths of the different axial-vector mesons. In particular, we evaluate the radiative decay into $K γ$ of the two $K_1(1270)$ states, recently claimed theoretically, and discuss the experimental values quoted so far on the assumpt…
The radiative decay width of a heavy Higgs boson $H \rightarrow W^+W^-γ$ for a {\it hard} photon is calculated in the Standard Model and its extension with anomalous $γWW$ couplings. Its dependence on the Higgs mass, the two unknown anomalous couplings, and the photon energy cutoff are studied in detail. We show that this radiative decay of a heavy Higgs is not very sensitive to a wide range of the anomalous couplings compared to the Standard Model result.
The radiative corrections to the pure leptonic decay $B_c \to \ellν_{\ell}$ up-to one-loop order is presented. How to cancel the infrared divergences appearing in the loop calculations, and the radiative decay $B_c \to \ellν_{\ell}γ$ is shown precisely. It is emphasized that the radiative decay may be separated properly and may compare with measurements directly as long as the theoretical `softness' of the photon corresponds to the experimental resolutions. Furthermore with a kind of non-relativistic constituent quark model, a kind of typical long distance contributions to the radiative decays…
扫码添加微信好友，提出您的宝贵建议 👇
💡 备注请填写：网站反馈
发表机构由 AI 从论文文本抽取，如发现错误，欢迎反馈修正建议。