Alexander Mitov

My work covers all high-energy particle colliders:

• Hadron colliders (Tevatron, LHC)
• Electron-positron colliders (LEP, future ILC)
• B-meson physics at B-factories (Belle, BaBar)
• Deep Inelastic Scattering (DIS) experiments (HERA, NuTeV).

Fixed order calculations to specific collider observables:

• Top physics: the exact NNLO corrections to top production at the Tevatron. This is the first ever NNLO calculation with 4 colored partons and/or massive fermions at hadron colliders. The precision achieved is, as far as I know, unparalleled in collider physics.
• Top-physics at hadron colliders: application of state of the art effective theory methods.
• B-physics: calculated the photon spectrum in B-decays to strage particles at NNLO
• B-physics: derived the most accurate prediction for the decay rate of B-mesons to strange particles.
• Energy spectrum of B-mesons in top-quark decay (with full account of the b-quark mass) at NLO.
• NNLO coefficient functions for quark and gluon production at e+e- colliders. Basic for NNLO fragmentation.
• The exact result for the NLO corrections to the total top-pair production cross-section at hadron colliders.
• The so-called threshold approximation to the NNLO total top-pair production cross-section at hadron colliders.
• The two-loop corrections for the heavy quark formfactor in QCD.

All-order soft gluon resummation: applications to specific observables and development of the basics techniques of resummation:

• Threshold resummation for massive quark-pair production at hadron colliders at NNLL
• The one-loop hard matching coefficients for massive quark-pair production at hadron colliders
• NNLL exponentiation of the heavy quark formfactor
• NNLL resummation for the jet function of a heavy quark
• NLL (and later NNLL) resummation for heavy quark production in CC DIS
• NLL (and later NNLL) resummation for b-quark production in top decay

All-order resummation of collinear singularities (massive and massless cases):

• The 3-loop (NNLO) time-like non-singlet (DGLAP) splitting functions of QCD.
• All NNLO quark- and gluon- initiated components of the perturbative fragmentation function in QCD.
• A general discussion of collinear singularities in observables and amplitudes can be found here.

Structure of gauge theory amplitudes and their singularities - especially with massive flavors:

• A factorization theorem that predicts the structure of massive QCD amplitudes in the limit of small masses.
• With the above derived in analytical form the two-loop amplitudes for heavy quark production at hadron colliders in the small mass limit
• Derived the soft-anomalous dimension matrix for massive quarks at two-loops
• Established the relation between IR singularities in amplitudes and soft-gluon resummation for related cross-sections
• Generalized the non-abelian exponentiation theorem for arbitrary gauge amplitudes and products of Wilson lines.

Calculational technology:

• Published a state-of-the-art program, Top++ , for the numerical evaluation of top-pair production at hadron colliders.
• A method for the evaluation of differential distributions directly in Mellin space with the help of Integration by parts Identities and difference equations.

• Studied the identification of the radion in the compact Randall-Sundrum model. Demonstrated the diagonalization of the effective action.
• Collider implications of a general Universal-Extra-Dimensons-like model with a multidimensional compact extra dimensions.

• Constructed explicit polynomial realization of the Gel'fand-(Weyl)-Zetlin basis for the representations of the quantum sl(3) algebra.
• Derived new summation formulas for q-hypergeometric functions.
• Studied a model of a self-interacting spinor field with higher derivatives. Solved the Bete-Salpeter equation in that model and demonstrated the existence of a (finely-tuned) bound state.