Analytic structure of all loop banana integrals

Using the Gelfand-Kapranov-Zelevinskĭ system for the primitive cohomology of an infinite series of complete intersection Calabi-Yau manifolds, whose dimension is the loop order minus one, we completely clarify the analytic structure of all banana integrals with arbitrary masses. In particular, we find that the leading logarithmic structure in the high energy regime, which corresponds to the point of maximal unipotent monodromy, is determined by a novel $$ \hat{\Gamma}\hbox{-} \mathrm{class} $$ Γ ̂ ‐ class evaluation in the ambient spaces of the mirror, while the imaginary part of the integral in this regime is determined by the $$ \hat{\Gamma}\hbox{-} \mathrm{class} $$ Γ ̂ ‐ class of the mirror Calabi-Yau manifold itself. We provide simple closed all loop formulas for the former as well as for the Frobenius κ-constants, which determine the behaviour of the integrals when the momentum square equals the sum of the masses squared, in terms of zeta values. We extend our previous work from three to four loops by providing for the latter case a complete set of (inhomogeneous) Picard-Fuchs differential equations for arbitrary masses. This allows to evaluate the banana integral in very short time to very high numerical precision for all values of the physical parameters. Using modular properties of the periods we determine the value of the maximal cut equal mass four-loop integral at the attractor points in terms of periods of modular weight two and four Hecke eigenforms and the quasiperiods of their meromorphic cousins.

A note on supergravity inflation in braneworld

We discuss supergravity inflation in braneworld cosmology for the class of potentials [Formula: see text] with [Formula: see text]. These minimal SUGRA models evade the [Formula: see text] problem due to a broken shift symmetry and can easily accommodate the observational constraints. In the high energy regime [Formula: see text], the numerical predictions and approximate analytic formulas are given for the scalar spectral index [Formula: see text] and tensor-to-scalar ratio [Formula: see text]. The models with smaller [Formula: see text] are preferred while the models with larger [Formula: see text] are out of the [Formula: see text] region. Remarkably, the [Formula: see text] correction to the energy density in Friedmann equation results in sub-Planckian inflaton excursions [Formula: see text].

From soft to hard radiation: the role of multiple scatterings in medium-induced gluon emissions

A proper understanding of the physics of medium-induced gluon emissions is known to be of critical importance to describe the properties of strongly interacting matter under extreme conditions. In this regard, many theoretical efforts have been directed towards obtaining analytical calculations which might help us discerning the underlying physical picture and the dominant dynamics for different regimes. These analytical approaches rely on approximations whose validity is analyzed here by comparing their results with a recently developed numerical evaluation which includes all-order resummation of multiple scatterings. More specifically, by quantitatively comparing the energy spectrum and rates, we observe that three different regimes — each with its corresponding physical picture — emerge naturally from the equations: the high-energy regime where the emission process is dominated by a single hard scattering, the intermediate-energy regime where coherence effects among multiple scatterings become fundamental, and the low-energy regime where the dynamics is again dominated by a single scattering but where one must include the suppression factor due to the probability of not having any further scatterings (which is obtained through the resummation of virtual terms).

Suppression of electroweak instanton processes in high-energy collisions

Electroweak instantons are a prediction of the Standard Model and have been studied in great detail in the past although they have not been observed. Earlier calculations of the instanton production cross-section at colliders revealed that it was exponentially suppressed at low energies, but may grow large at energies (much) above the sphaleron mass. Such calculations faced difficulty in the breakdown of the instanton perturbation theory in the high-energy regime. In this paper, we review the calculation for the electroweak instanton cross-section using the optical theorem, including quantum effects arising from interactions in the initial state and show that this leads to an exponential suppression of the cross-section at all energies, rendering the process unobservable.

Hubble inflation in Randall–Sundrum type II model

We study a braneworld Randall–Sundrum type II (RSII) model using the Hamilton–Jacobi formalism. We extend the standard inflationary parameters and the flow equations for this braneworld scenario. We investigate the conditions that reduce the infinite number of flow equations into a finite number and confirm that by considering one of the inflationary parameters that vanishes, the Hubble expansion rate gets a polynomial form in both General Relativity (GR) and in the high-energy regime of RSII. We also show that if one sets this inflationary parameter to a constant value, the model features a nonpolynomial form of the Hubble expansion rate. The form of the Hubble parameter in this case is different in GR and RSII. Next, we consider a single-scalar field model with a Hubble expansion rate behaving as [Formula: see text] and show that compared to GR, the RSII model has a smaller tensor-to-scalar ratio and larger spectral index for [Formula: see text]. Therefore, RSII model leads to better predictions than GR.

On braneworld monomial inflation

We investigate a monomial inflationary scalar model in the braneworld Randall–Sundrum type II model. In the high-energy regime, we determine the slow-roll parameters as well as the perturbation spectrum of the model. According to the known observational data, the corresponding results and the solutions of the equation of motion on the brane are discussed.

On braneworld inverse power-law inflation

In the framework of the braneworld Randall–Sundrum type II model, we investigate an inflationary scalar model in the high-energy regime. In this regime, the slow-roll parameters and the perturbation spectrum of the model are derived. The corresponding results are dealt with according to the known observational data. Then the solutions to the equations of motion on the brane are given.

The High-Energy Photoproduction of Light-Quark Pseudoscalar and Scalar Meson at GlueX

The high-energy photoproduction of light-quark pseudoscalar and scalar mesons is an effective tool for understanding the properties of strong interaction in the nonperturbative regime. It has been investigated theoretically using Regge-cut phenomenology with massive quasi-particle exchange in the high-energy regime, and the linearly polarized photon beam asymmetry [Formula: see text] can provide insight into the dominant production mechanism. In the low-energy region, it can provide constraints on ”background” to baryon resonance extraction. With an almost 50-year history, intensive experiments on meson photoproduction are growing vigorously at several international laboratories, such as JLab, ELSA, and MAMI. Recently the beam asymmetry [Formula: see text] in high-energy [Formula: see text] photoproduction has been measured at GlueX, which is the first measurement both from the GlueX experiment and the 12 GeV upgraded JLab. The highest precision measurement of the [Formula: see text] asymmetry and the first measurement of [Formula: see text] beam asymmetry at a beam energy above 3 GeV are presented. A broad meson photoproduction project, including scalar meson [Formula: see text], is under way at GlueX. In the proceedings, we report the beam asymmetry results for [Formula: see text] photoproduction at GlueX, as well as preliminary results for scalar meson photoproduction in the [Formula: see text] and [Formula: see text] channels.