Classical soft graviton theorem rewritten

Classical soft graviton theorem gives the gravitational wave-form at future null infinity at late retarded time u for a general classical scattering. The large u expansion has three known universal terms: the constant term, the term proportional to 1/u and the term proportional to ln u/u2, whose coefficients are determined solely in terms of the momenta of incoming and the outgoing hard particles, including the momenta carried by outgoing gravitational and electromagnetic radiation produced during scattering. For the constant term, also known as the memory effect, the dependence on the momenta carried away by the final state radiation / massless particles is known as non-linear memory or null memory. It was shown earlier that for the coefficient of the 1/u term the dependence on the momenta of the final state massless particles / radiation cancels and the result can be written solely in terms of the momenta of the incoming particles / radiation and the final state massive particles. In this note we show that the same result holds for the coefficient of the ln u/u2 term. Our result implies that for scattering of massless particles the coefficients of the 1/u and ln u/u2 terms are determined solely by the incoming momenta, even if the particles coalesce to form a black hole and massless radiation. We use our result to compute the low frequency flux of gravitational radiation from the collision of massless particles at large impact parameter.

More on heavy-light bootstrap up to double-stress-tensor

We investigate the heavy-light four-point function up to double-stress-tensor, supplementing 1910.06357. By using the OPE coefficients of lowest-twist double-stress- tensor in the literature, we find the Regge behavior for lowest-twist double-stress-tensor in general even dimension within the large impact parameter regime. In the next, we perform the Lorentzian inversion formula to obtain both the OPE coefficients and anomalous dimensions of double-twist operators [$$ \mathcal{O} $$ O H$$ \mathcal{O} $$ O L]n,J with finite spin J in d = 4. We also extract the anomalous dimensions of double-twist operators with finite spin in general dimension, which allows us to address the cases that ∆L is specified to the poles in lowest-twist double-stress-tensors where certain double-trace operators [$$ \mathcal{O} $$ O L$$ \mathcal{O} $$ O L]n,J mix with lowest-twist double-stress-tensors. In particular, we verify and discuss the Residue relation that deter- mines the product of the mixed anomalous dimension and the mixed OPE. We also present the double-trace and mixed OPE coefficients associated with ∆L poles in d = 6, 8. In the end, we turn to discuss CFT2, we verify the uniqueness of double-stress-tensor that is consistent with Virasoso symmetry.

BFKL equation in the next-to-leading order: solution at large impact parameters

In this paper, we show (1) that the NLO corrections do not change the power-like decrease of the scattering amplitude at large impact parameter ($$b^2 \,>\,r^2 \exp ( 2{\bar{\alpha }}_S\eta (1 + 4 {\bar{\alpha }}_S) )$$b2>r2exp(2α¯Sη(1+4α¯S)), where r denotes the size of scattering dipole and $$\eta = \ln (1/x_{Bj} )$$η=ln(1/xBj) for DIS), and, therefore, they do not resolve the inconsistency with unitarity; and (2) they lead to an oscillating behaviour of the scattering amplitude at large b, in direct contradiction with the unitarity constraints. However, from the more practical point of view, the NLO estimates give a faster decrease of the scattering amplitude as a function of b, and could be very useful for description of the experimental data. It turns out, that in a limited range of b, the NLO corrections generates the fast decrease of the scattering amplitude with b, which can be parameterized as $$N\, \propto \,\exp ( -\,\mu \,b )$$N∝exp(-μb) with $$\mu \, \propto \,1/r$$μ∝1/r in accord with the numerical estimates in Cepila et al. (Phys Rev D 99(5):051502, 10.1103/PhysRevD.99.051502, arXiv:1812.02548 [hep-ph], 2019).

Charged Lepton Spectra from Hot-Spot Evaporation

Spectra for the emission of charged leptons from evaporating hot-spots of preconfining phase in SU(2) Yang-Mills thermodynamics are computed. Specifically, we consider charged single and dileptons with their spectra being functions of energy and invariant mass, respectively. In the former case, our results relate to narrow and correlated electron and positron peaks measured in supercritical heavy-ion collisions performed at GSI in the 1980s. In the latter case, we point out how strongly the spectra depend on typical kinematic cuts (CDF analysis of Tevatron Run II data). We also propose a scenario on how muon events of anomalously high multiplicity and large impact-parameter modulus arise in the Tevatron data.

Correlated stopping of relativistic electrons in supercompressed DT fuel

The electromagnetic stopping of intense and relativistic electron beams (REB) arising from femtosecond lasers interacting with a precompressed deuterium–tritium (DT) fuel is investigated within the Bohr–Fermi formalism with a large impact parameter. Dynamical intrabeam correlations in the target are shown to be quantitatively significant for various arrangements of projectile electrons and the overall REB penetration in the DT fuel.

INTERACTION OF TACHYONS WITH MATTER

A new interaction mechanism of superluminal particles with matter is suggested. Tachyons are described by a real Proca field with negative mass square, coupled to a current of subluminal matter. The potential of a static point source in this field theory is a damped periodic function with 1/r-decay. We treat this potential as a perturbation of the Coulomb potential, and study its effects on cross-sections and energy levels. In the limit of large impact parameter, the periodicity of the potential has a pronounced effect on the classical cross-section, which gets singular at the accumulating extrema of the scattering angle. In this limit we define the cross-section wave mechanically, by semiclassical rainbow scattering. The impact of the tachyon potential on the energy levels of hydrogen and hydrogenic ions is calculated by means of Bohr–Sommerfeld quantization. Estimates for the tachyon mass (3 keV) and the coupling constant of the tachyon potential are derived on the basis of high-precision Lamb shift measurements.

DECOHERENT SCATTERING OF LIGHT PARTICLES IN A D-BRANE BACKGROUND

We discuss the scattering of two light particles in a D-brane background. It is known that, if one light particle strikes the D-brane at small impact parameter, quantum recoil effects induce entanglement entropy in both the excited D-brane and the scattered particle. In this letter we compute the asymptotic "out" state of a second light particle scattering off the D-brane at large impact parameter, showing that it also becomes mixed as a consequence of quantum D-brane recoil effects. We interpret this as a non-factorizing contribution to the superscattering operator $ for the two light particles in a Liouville D-brane background, that appears when quantum D-brane excitations are taken into account.