606 research outputs found
Hadroproduction of t anti-t pair in association with an isolated photon at NLO accuracy matched with parton shower
We simulate the hadroproduction of a t anti-t pair in association with a hard
photon at LHC using the PowHel package. These events are almost fully inclusive
with respect to the photon, allowing for any physically relevant isolation of
the photon. We use the generated events, stored according to the Les-Houches
event format, to make predictions for differential distributions formally at
the next-to-leading order (NLO) accuracy and we compare these to existing
predictions accurate at NLO using the smooth isolation prescription of
Frixione. We also make predictions for distributions after full parton shower
and hadronization using the standard experimental cone-isolation of the photon.Comment: 21 pages, 17 figures, version accepted for publication in JHE
A subtraction scheme for computing QCD jet cross sections at NNLO: integrating the subtraction terms I
In previous articles we outlined a subtraction scheme for regularizing
doubly-real emission and real-virtual emission in next-to-next-to-leading order
(NNLO) calculations of jet cross sections in electron-positron annihilation. In
order to find the NNLO correction these subtraction terms have to be integrated
over the factorized unresolved phase space and combined with the two-loop
corrections. In this paper we perform the integration of all one-parton
unresolved subtraction terms
Hadroproduction of t anti-t pair with two isolated photons with PowHel
We simulate the hadroproduction of a t anti-t pair in association with two
isolated hard photons at 13 TeV LHC using the PowHel package. We use the
generated events, stored according to the Les-Houches event format, to make
predictions for differential distributions formally at the next-to-leading
order (NLO) accuracy. We present predictions at the hadron level employing the
cone-type isolation of the photons used by experiments. We also compare the
kinematic distributions to the same distributions obtained in the t anti-t H
final state when the Higgs-boson decays into a photon pair, to which the
process discussed here is an irreducible background.Comment: 18 pages, 11 figures, minor changes, version submitted for
publicatio
Új fizika keresése a CERN CMS detektorával = Search for new physics with the CMS detector at CERN
A kikĂĽldöttek munkájának eredmĂ©nyekĂ©nt megvalĂłsult a CMS mĂĽonkamrák helyzetmeghatározĂł rendszerĂ©nek fejlesztĂ©sĂ©vel, megĂ©pĂtĂ©sĂ©vel, kiprĂłbálásával Ă©s ĂĽzemeltetĂ©sĂ©vel kapcsolatos összes cĂ©lkitűzĂ©sĂĽnk. MegtörtĂ©nt az elsĹ‘ ĂĽzemi tapasztalatok összegyűjtĂ©se, az Ă©szlelt hibák javĂtása, Ă©s a felkĂ©szĂĽlĂ©s az Ăşj mĂ©rĂ©si idĹ‘szakaszra. A tevĂ©kenysĂ©g másik ága az Ĺ‘szi mĂ©rĂ©sek kiĂ©rtĂ©kelĂ©se, illetve a kiĂ©rtĂ©kelĂ©si mĂłdszerek tökĂ©letesĂtĂ©se volt a szerzett tapasztalatok alapján. A cĂ©lkitűzĂ©seken tĂşlmenĹ‘en foglalkoztunk a Pixel detektor idĹ‘zĂtĂ©sĂ©vel is. Kozmikus mĂĽonok segĂtsĂ©gĂ©vel a Pixel adatrögzĂtĂ©sĂ©nek idejĂ©t a kozmikus esemĂ©nyt kiválasztĂł detektor idejĂ©hez hangoltuk, majd a Pixel detektor idĹ‘zĂtĂ©sĂ©t az LHC-ben törtĂ©nĹ‘ elsĹ‘ ĂĽtközĂ©sekhez igazĂtottuk, illetve a detektor moduljainak egyedi idĹ‘zĂtĂ©sĂ©t összehangoltuk. Az adatkiĂ©rtĂ©kelĂ©s terĂ©n a szuperszimmetrikus jelensĂ©gek keresĂ©sĂ©ben vettĂĽnk rĂ©szt. Csoportunk csatlakozott a CMS SUSY-csoportjában alakult egy-leptonos alcsoporthoz Ă©s elvĂ©gezte a csoport által kijelölt RA4 referencia-analĂzist. Komoly elĹ‘relĂ©pĂ©s törtĂ©nt a proton-proton ĂĽtközĂ©sben hipotetikusan keletkezĹ‘ fekete lyukak modelljĂ©nek vizsgálatában is: a BlackMax program segĂtsĂ©gĂ©vel szimulált adatokon vizsgáltuk a jelensĂ©g megfigyelĂ©sĂ©nek lehetĹ‘sĂ©geit a CMS-nĂ©l. | As a result of the work carried out at CERN, our group achieved all the planned goals related to the CMS muon barrel positioning system: development, construction, testing and maintainance. We have collected the first experiences of operation, corrected the faulty elements and prepared to the new period of operation. The other segment of our activities was evaluation of the data from fall 2008 and the improvement of the data analysis software based upon the collected experiance during operation. In addition to the original plans, we also worked on the timing of the Pixel detector. Using cosmic muons we adjusted the time of data recording to the time of the subdetector that selected the cosmic event. Next, we adjusted the time of the Pixel detector to the time of the first collisions in the LHC. Furthermore, we synchronized the modules of the detector. In the field of data analysis we participated in searching for the manifestation of supersymmetry. Our group joined the single-lepton subgroup of the CMS SUSY working group and carried out the RA4 reference analysis requested by the subgroup. We also made significant advancement in studying the model for the production of microscopic black holes assumed in proton-proton collisions: using data simulated with the BlackMax computer program, we searched for channels of detection of such events at CMS
Precise prediction for the mass of the boson in gauged U(1) extensions of the standard model
We present the one-loop radiative corrections to the muon decay in U(1)
extensions of the standard model. We compute the mass of the boson using
those corrections and compare it to an approximation of the complete one-loop
prediction implemented in automated computational tools. We point out that the
truncation of the complete formulas become unreliable if the mass of the
boson, corresponding to the new U(1) gauge group is larger than about 1
TeV.Comment: 13 pages, 2 figure
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