Zobrazeno 1 - 10
of 3 337
pro vyhledávání: '"Román N"'
Autor:
Lee, Roman N.
We consider the problem of finding the set of classical polylogarithmic functions $\text{Li}_n$ with branching locus determined by the solution of $p_1\cdot p_2\cdot \ldots \cdot p_n=0$, where $p_1,\ldots, p_n$ are irreducible polynomials of several
Externí odkaz:
http://arxiv.org/abs/2407.12503
Polarized semi-inclusive deep-inelastic scattering (SIDIS) is a key process in the quest for a resolution of the proton spin puzzle. We present the complete results for the polarized SIDIS process at next-to-next-to-leading order (NNLO) in perturbati
Externí odkaz:
http://arxiv.org/abs/2404.09959
Autor:
Krachkov, Petr A., Lee, Roman N.
We derive an analytical expression for the contribution of the order $m\alpha^2 (Z\alpha)^6$ to the hydrogen Lamb shift which comes from the diagrams for radiative corrections to the Wichmann-Kroll potential. We use modern methods of multiloop calcul
Externí odkaz:
http://arxiv.org/abs/2311.05860
We calculate the total Born cross section of the $e^+e^-$-pair production by an electron in the field of a nucleus (trident process) using the modern multiloop methods. For general energies we obtain the cross section in terms of converging power ser
Externí odkaz:
http://arxiv.org/abs/2309.02904
Autor:
Lee, Roman N., von Manteuffel, Andreas, Schabinger, Robert M., Smirnov, Alexander V., Smirnov, Vladimir A., Steinhauser, Matthias
We present analytical results for all master integrals for massless three-point functions, with one off-shell leg, at four loops. Our solutions were obtained using differential equations and direct integration techniques. We review the methods and pr
Externí odkaz:
http://arxiv.org/abs/2309.00054
Autor:
Krachkov, Petr A., Lee, Roman N.
We revisit the contributions of order $\alpha^2(Z\alpha)^5m$ and $\alpha^2(Z\alpha)E_F$, respectively, to the Lamb shift and to the hyperfine splitting from mixed self-energy-vacuum-polarization diagrams, involving fermionic loop. We use modern multi
Externí odkaz:
http://arxiv.org/abs/2306.13369
Autor:
Krachkov, Petr A., Lee, Roman N.
We calculate the first Coulomb correction to the spectra of two processes: the electron bremsstrahlung and electron-positron photoproduction in the Coulomb field. We show that, in contrast to the results obtained in the Born approximation and in the
Externí odkaz:
http://arxiv.org/abs/2212.00978
Autor:
Lee, Roman N., Pikelner, Andrey F.
We use dimensional recurrence relations and analyticity to calculate four-loop propagator-type master integrals in the heavy-quark effective theory. Compared to previous applications of the DRA method, we apply a new technique of fixing homogeneous s
Externí odkaz:
http://arxiv.org/abs/2211.03668
We calculate the small angle expansion of the four-loop QCD cusp anomalous dimension. As a byproduct of our calculation, we also obtain the four-loop anomalous dimension of the heavy-quark field in HQET. The validity of the calculational setup is cro
Externí odkaz:
http://arxiv.org/abs/2208.09277
Autor:
Ignatov, Fedor, Lee, Roman N.
We consider the charge asymmetry in the differential cross section of the process $e^+e^- \rightarrow \pi^+\pi^-$. Experimental data show large deviations from the results of the available theoretical calculations. Motivated by this fact, we revisit
Externí odkaz:
http://arxiv.org/abs/2204.12235