A5064611547- Particle physics theoretical and experimental studies
- High-Energy Particle Collisions Research
- Quantum Chromodynamics and Particle Interactions
- Particle Detector Development and Performance
- Black Holes and Theoretical Physics
- Computational Physics and Python Applications
- Cosmology and Gravitation Theories
- Distributed and Parallel Computing Systems
- Superconducting Materials and Applications
- Advanced Data Storage Technologies
- Dark Matter and Cosmic Phenomena
- Scientific Computing and Data Management
- International Science and Diplomacy
- Statistical Distribution Estimation and Applications
- Advanced Topics in Algebra
- Algebraic structures and combinatorial models
- Computational Fluid Dynamics and Aerodynamics
- History and advancements in chemistry
- Quantum Mechanics and Applications
- Radiation Effects in Electronics
- Bayesian Methods and Mixture Models
- Neutrino Physics Research
- Quantum and Classical Electrodynamics
- Nonlinear Waves and Solitons
- Cold Atom Physics and Bose-Einstein Condensates
Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas
2024
University of Cambridge
2014-2023
RWTH Aachen University
2018-2021
Cavendish Hospital
2018
Bridge University
2016
European Organization for Nuclear Research
2011-2014
Stony Brook University
2009-2010
Deutsches Elektronen-Synchrotron DESY
2006-2008
University of Hawaiʻi at Mānoa
2005
University of Hawaii System
2004-2005
We compute the next-to-next-to-leading order (NNLO) QCD correction to total cross-section for reaction gg \to t\bar t + X. Together with partonic channels we computed previously, result derived in this letter completes set of NNLO corrections top pair production at hadron colliders. Supplementing fixed results soft-gluon resummation logarithmic accuracy estimate that theoretical uncertainty observable due unknown higher is about 3% LHC and 2.2% Tevatron. observe a good agreement between...
Combining our results for various O(alpha[s]) corrections to the weak radiative B-meson decay, we are able present first estimate of branching ratio at next-to-next-to-leading order in QCD. We find B(B[over ]-->X[s]gamma)=(3.15+/-0.23) x 10(-4) Egamma>1.6 GeV B[over ]-meson rest frame. The four types uncertainties:nonperturbative (5%), parametric (3%), higher-order and m(c)-interpolation ambiguity (3%) have been added quadrature obtain total error.
We compute the Next-to-Next-to-Leading Order (NNLO) QCD corrections to partonic reaction that dominates top-pair production at Tevatron. This is first ever NNLO calculation of an observable with more than two colored partons, and/or massive fermions, hadron colliders. Augmenting our fixed order soft-gluon resummation through Logarithmic (NNLL) accuracy, we observe predicted total inclusive cross-section exhibits a very small perturbative uncertainty, estimated +-2.7%. expect once all...
Incorporating all recent theoretical advances, we resum soft-gluon corrections to the total $t\bar t$ cross-section at hadron colliders next-to-next-to-leading logarithmic (NNLL) order. We perform resummation in well established framework of Mellin $N$-space resummation. exhaustively study sources systematic uncertainty like renormalization and factorization scale variation, power suppressed effects missing two- higher-loop corrections. The inclusion NNLL brings only a minor decrease...
A bstract We compute the next-to-next-to-leading order QCD correction to total inclusive top pair production cross-section in reaction $ qg\to t\overline{t}+X . find moderate \mathcal{O} (1%) central values at both Tevatron and LHC. The scale variation of remains unchanged is significantly reduced that recently introduced approximation based on high-energy limit deviates from exact result. results derived present work are included version 1.4 program Top++. Work towards computing gg\to ongoing.
This is a second paper in our ongoing calculation of the next-to-next-to-leading order (NNLO) QCD correction to total inclusive top-pair production cross-section at hadron colliders. In this we calculate reaction $q\bar q \to t\bar t + q\bar q$ which was not considered previous work on +X$ due its phenomenologically negligible size. We also all remaining fermion-pair-initiated partonic channels $qq', q'$ and $qq$ that contribute starting from NNLO. The contributions these reactions for...
We present the first complete next-to-next-to-leading order (NNLO) QCD predictions for differential distributions in top-quark pair production process at LHC. Our results are derived from a fully partonic Monte Carlo calculation with stable top quarks which involves no approximations beyond fixed-order truncation of perturbation series. The NNLO corrections improve agreement between existing LHC measurements [V. Khachatryan et al. (CMS Collaboration), Eur. Phys. J. C 75, 542 (2015)] and...
In this work we present for the first time predictions top-quark pair differential distributions at LHC NNLO QCD accuracy and including EW corrections. For latter include not only contributions of ${\cal O}(\alpha_s^2 \alpha)$, but also those order O}(\alpha_s \alpha^2)$ O}( \alpha^3)$. Besides providing phenomenological all main with stable top quarks, study following issues. 1) The effect photon PDF on top-pair spectra: find it to be strongly dependent set used -- especially $p_T$...
The successful operation of the Large Hadron Collider (LHC) and excellent performance ATLAS, CMS, LHCb ALICE detectors in Run-1 Run-2 with $pp$ collisions at center-of-mass energies 7, 8 13 TeV as well giant leap precision calculations modeling fundamental interactions hadron colliders have allowed an extraordinary breadth physics studies including measurements a variety processes. LHC results so far confirmed validity Standard Model particle up to unprecedented energy scales great sectors...
We calculate all major differential distributions with stable top-quarks at the LHC. The calculation covers multi-TeV range that will be explored during LHC Run II and beyond. Our results are in form of high-quality binned distributions. offer predictions based on three different parton distribution function (pdf) sets. In near future we make our available also more flexible fastNLO format allows fast re-computation any other pdf set. order to able extend into have had derive a set dynamic...
We derive the threshold-resummed total cross section for heavy quark production in hadronic collisions accurate to next-to-next-to-leading logarithm, employing recent advances on soft anomalous dimension matrices massive pair relevant kinematic limit. also relation between threshold resummations fixed kinematics and inclusive section. As a check of our results, we have verified that they reproduce all poles color-averaged $q\overline{q}\ensuremath{\rightarrow}t\overline{t}$ amplitudes at two...
We determine the dominant missing Standard Model (SM) contribution to top quark pair forward-backward asymmetry at Tevatron. Contrary past expectations, we find a large, around 27%, shift relative well-known value of inclusive in next-to-leading order (NLO) QCD. Combining all known corrections, that AFB^{SM} = 0.095 +- 0.007. This is agreement with latest D0 measurement [V. M. Abazov et al. (D0 Collaboration), Phys. Rev. D 90, 072011 (2014)] AFB^{D0} 0.106+- 0.03 and about 1.5 sigma below...
We compute the NNLO QCD corrections to three-photon production at LHC. This is first calculation for a $2\to 3$ process. Our exact, except scale-independent part of two-loop finite remainder which included in leading color approximation. estimate size missing and find them be phenomenologically negligible. compare our predictions with available 8 TeV measurement from ATLAS collaboration. that inclusion eliminates existing significant discrepancy respect NLO predictions, paving way precision...
We calculate the NNLO QCD corrections to diphoton production with an additional jet at LHC. Our calculation represents first NNLO-accurate prediction for transverse momentum distribution of system. The improvement in accuracy theoretical is significant, by a factor up four relative NLO QCD. exact except finite remainder two-loop amplitude which included leading color. numerical impact this approximated contribution small. results work are expected further our understanding Higgs boson sector...
Multijet rates at hadron colliders provide a unique possibility for probing quantum chromodynamics (QCD), the theory of strong interactions. By comparing predictions with collider data, one can directly test perturbative QCD, extract fundamental parameters like coupling α_{s}, and search physics beyond standard model. In this work we calculate, first time, next-to-next-to-leading order (NNLO) QCD corrections to typical three-jet observables differential three-to-two jet ratios. The...
A bstract We calculate a comprehensive set of spin correlations and differential distributions in top-quark pair production decay to dilepton final states. Our calculation is performed the Narrow Width Approximation. This first time such complete study at next-to-next-to leading order QCD. Both inclusive fiducial are presented analyzed. Good agreement between NNLO QCD predictions data found. demonstrate that it possible perform high-precision comparisons fixed-order calculations with...
A bstract Flavour tagging is technically challenging on the experimental side. However, it suffers from a more fundamental problem theoretical point of view, in particular when implemented fixed-order perturbation theory. It turns out that an infrared-safe definition flavoured jet intricate due to singularities induced by emission quark-anti-quark pairs negligible energy. Although this issue has been addressed modification standard k T algorithm, situation not entirely satisfactory as most...
A bstract In this work we perform the first ever calculation of jet event shapes at hadron colliders next-to-next-to leading order (NNLO) in QCD. The inclusion higher corrections removes shape difference observed between data and next-to-leading predictions. theory uncertainty NNLO is comparable to, or slightly larger than, existing measurements. Except for narrow kinematical ranges where all-order resummation becomes important, predictions considered present are reliable. As a prime...
We present the two-loop virtual QCD corrections to production of heavy quarks in gluon fusion. The results are exact limit when all kinematical invariants large compared mass quark up terms suppressed by powers heavy-quark mass. Our derivation uses a simple relation between massless and massive scattering amplitudes as well direct calculation amplitude at two loops. presented here together with those obtained previously for quark-quark form important parts next-to-next-to-leading order...
Using the recently derived NNLO cross sections \cite{Czakon:2013goa}, we provide NNLO+NNLL theoretical predictions for top quark pair production based on all available PDF sets, and compare them with most precise LHC Tevatron data. In this comparison study in detail uncertainty scale, $m_t$ $\alpha_s$ dependence of each set. Next, observe that provides a powerful direct constraint gluon at large $x$, include data consistently into global fit. We then explore phenomenological consequences...
We study two-loop anomalous dimension matrices in QCD and related gauge theories for products of Wilson lines coupled at a point. verify by an analysis Euclidean space that the contributions to these from diagrams link three massive do not vanish general. show, however, two-to-two processes matrix is diagonal same color-exchange basis as one-loop arbitrary masses absolute threshold scattering 90 degrees center mass. This result important applications resummation heavy quark production.
We present the first exact analytic result for all partonic channels contributing to total cross section production of a pair heavy flavors in hadronic collisions NLO QCD. Our calculation is step derivation top quark at NNLO QCD, which cornerstone precision LHC program. results uncover analytical structures behind observables with higher orders. They also reveal surprising and non-trivial implications kinematics close threshold.