Differential cross section of processes with high energy $p(\bar p)p$ collisions in frames of QED: creation of scalar, pseudoscalar and lepton pair - are considered in Weizsäcker - Williams approximation. In frames of QCD processes with conversion of initial proton (antiproton) to fermionic jets accompanied with one gluon jet as well as the state of two gluons and quark-antiquark pair (with out rapidity gap) are considered in frames of effective Reggion action of theory of Lipatov. Process of creation of a Higgs boson accompanied with two fermionic jets is considered. The azimuthal correlation in process of two gluon jet separated by rapidity gap is investigated. Effects of gluon reggeization are taken into account. Some distributions are illustrated by numerical calculations.
The QCD$\times$QED factorization is studied for two-body non-leptonic and semi-leptonic $B$ decays with heavy-light final states. These non-leptonic decays, like $\bar{B}^0_{(s)}\to D^+_{(s)} π^-$ and $\bar{B}_d^0 \to D^+ K^-$, are among the theoretically cleanest non-leptonic decays as penguin loops do not contribute and colour-suppressed tree amplitudes are suppressed in the heavy-quark limit or even completely absent. Advancing the theoretical calculations of such decays requires therefore also a careful analysis of QED effects. Including QED effects does not alter the general structure of …
Istituto Nazionale di Fisica Nucleare, Sezione di Padova（意大利国家核物理研究所帕多瓦分部）；PRISMA ++ Cluster of Excellence & Mainz Institute for Theoretical Physics Johannes Gutenberg University（约翰内斯·古腾堡大学）；Department of Physics & LEPP, Cornell University（康奈尔大学）
We present a detailed analysis of QED corrections to $\bar{B} \to \bar{K} \ell^+ \ell^-$ decays at the double-differential level. Cancellations of soft and collinear divergences are demonstrated analytically using the phase space slicing method. Whereas soft divergences are found to cancel at the differential level, the cancellation of the hard-collinear logs $\ln m_\ell$ require, besides photon-inclusiveness, a specific choice of kinematic variables. In particular, hard-collinear logs in the lepton-pair invariant mass distribution ($q^2$), are sizeable and need to be treated with care when co…
We showcase the calculation of the master integrals needed for the two loop mixed QCD-QED virtual corrections to the neutral current Drell-Yan process $(q\bar{q}\rightarrow l^+ l^-)$. After establishing a basis of 51 master integrals, we cast the latter into canonical form by using the Magnus algorithm. The dependence on the lepton mass is then expanded such that potentially large logarithmic contributions are kept. After determining all boundary constants, we give the coefficients of the Taylor series around four space-time dimensions in terms of generalized polylogarithms up to weight four.
Using analytic results obtained in a meson effective theory, that includes all infrared sensitive logs, we build a dedicated Monte Carlo framework to describe QED corrections in $\bar B \to \bar K \ell^+\ell^-$ for a generic form factor. For the neutral mode $\bar B^0 \to \bar K^0 \ell^+\ell^-$, we perform a detailed numerical comparison versus those obtained with the general-purpose photon-shower tool PHOTOS. The comparison indicates a good agreement, at the few per-mil level, when focusing on the rare mode only. In addition, our framework allows us to investigate the impact of the charmonium…
In these lecture notes the basics of QED corrections to hadronic decays are reviewed with special emphasis on conceptual (e.g. counting and tracking of infrared sensitive logs) rather than numerical aspects. General matters are illustrated for the cases of increased complexity and decreased inclusiveness: $e^+ e^- \to hadrons$, the leptonic decay $π^+ \to \ell^+ \bar ν$ and the semileptonic decay $B \to π\ell^+ \bar ν$. The non-trivial and ongoing efforts of including structure dependence are very briefly outlined.
We consider the radiation of a soft gluon ($g$) and a soft quark-antiquark ($q{\bar q}$) pair in QCD hard scattering. In the soft limit the scattering amplitude has a singular behaviour that is factorized and controlled by a soft current, which has a process-independent structure in colour space. We evaluate the soft $gq{\bar q}$ current at the tree level for an arbitrary multiparton scattering process. The irreducible correlation component of the current includes strictly non-abelian terms and also terms with an abelian character. Analogous abelian correlations appear for soft photon-lepton-a…
The master integrals for the mixed QCD-QED two-loop virtual corrections to the charged-current Drell-Yan process $q\bar{q}^{\prime} \rightarrow \ell ν$ are computed analytically by using the differential equation method. A suitable choice of master integrals makes it successful to cast the differential equation system into the canonical form. We keep the dependence on charged lepton mass in the building of differential equations and then expand the system against the ratio of small charged lepton mass to large $W$-boson mass. In such a way the final results will contain large logarithms of the…
In slow collisions of two bare nuclei with the total charge number larger than the critical value, $Z_{\rm cr} \approx 173$, the initially neutral vacuum can spontaneously decay into the charged vacuum and two positrons. Detection of the spontaneous emission of positrons would be the direct evidence of this fundamental phenomenon. However, the spontaneous emission is generally masked by the dynamical positron emission, which is induced by a strong time-dependent electric field created by the colliding nuclei. In our recent paper [I.A. Maltsev et al., Phys. Rev. Lett. 123, 113401 (2019)] it has…
The three-loop QED contributions to the $g-2$ of charged leptons with two internal fermion loops and a class of Kampé de Fériet series
利用Mellin-Barnes（MB）表象技术，重新讨论了具有两个内部闭合费米子环的带电轻子（在$g-2$文献中有时称为$A^{(6)}_3\left(\frac{m_1}{m_2}, \frac{m_1}{m_3}\right)$）的三圈QED质量对$g-2$的贡献.μ子和$τ$轻子反常磁矩$A^{(6)}_{3,μ}$和$A^{(6)}_{3,τ}$的结果被推广到它们的精确表达式，它们被认为是轻子质量比的级数展开。对电子$A^{(6)}_{3,e}$反常磁矩的贡献也以封闭形式明确给出。除此之外，我们表明，不同的系列表示来自MB表示集体收敛的所有可能的质量值。这种意想不到的行为是有关的事实，这些系列发挥双重超几何级数，属于一类的Kampé de Fériet系列，我们证明了具有相同的简单收敛性和解析延拓性质的Appell $F_1$双重超几何级数。
The sixth order QED radiative corrections to lepton anomalies due to the fourth order vacuum polarization insertions within the Mellin-Barnes representation
