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Alexander Mitov

Brief overview of my scientific interests

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My personal taste is in problems of physics that are not necessarily easy to solve, but have important, experimentally relevant outcome. I like to challenge established beliefs and try to get beyond what is known.

My current research is in precision collider phenomenology. That involves higher order QCD (Quantum Chromodynamics) corrections to collider observables. My work is the state of the art in the corresponding subjects. More information on why precision collider phenomenology is very important - especially nowadays - can be found in my Blog.

I have also worked on model building (models with extra space dimensions) and more formal mathematical physics. I am keenly interested in the problems of Gravity, Dark Matter, CP violation, extra dimensions and more.

Last Updated ( Saturday, 13 November 2010 01:21 )

QCD and particle colliders

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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.
Last Updated ( Monday, 25 June 2012 10:35 )

Models with extra space dimensions

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  • 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.
Last Updated ( Tuesday, 23 November 2010 23:41 )

Mathematical physics

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  • 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.
Last Updated ( Tuesday, 23 November 2010 23:42 )