A Monte Carlo event generator is implemented for a two-Higgs-doublet model with maximal CP symmetry, the MCPM. The model contains five physical Higgs bosons; the
ρ
′, behaving similarly to the ...standard-model Higgs boson, two extra neutral bosons
h
′ and
h
″, and a charged pair
H
±
. The special feature of the MCPM is that, concerning the Yukawa couplings, the bosons
h
′,
h
″ and
H
±
couple directly only to the second-generation fermions but with strengths given by the third-generation-fermion masses. Our event generator allows the simulation of the Drell–Yan-type production processes of
h
′,
h
″ and
H
±
in proton–proton collisions at LHC energies. Also the subsequent leptonic decays of these bosons into the
μ
+
μ
−
,
μ
+
ν
μ
and
channels are studied as well as the dominant background processes. We estimate the integrated luminosities needed in
pp
collisions at center-of-mass energies of 8 and 14 TeV for significant observations of the Higgs bosons
h
′,
h
″ and
H
±
in these muonic channels.
AbstractQED Compton scattering at HERA is proposed for a measurement of the proton structure function F2 at low momentum transfers Q2. It is shown that the analysis of inelastic QED Compton events ...allows the extension of present HERA structure function measurements to a kinematic domain, which up to now was only accessed in fixed target data. Preliminary results of such a measurement performed by the H1 Collaboration are presented. The results are in good agreement with the measurements from fixed target experiments wherever they overlap.
A Monte Carlo event generator is implemented for a two-Higgs-doublet model with maximal CP symmetry, the MCPM. The model contains five physical Higgs bosons; the ρ', behaving similarly to the ...standard-model Higgs boson, two extra neutral bosons h and h", and a charged pair H.sup.±. The special feature of the MCPM is that, concerning the Yukawa couplings, the bosons h', h" and H.sup.+ or - couple directly only to the second-generation fermions but with strengths given by the third-generation-fermion masses. Our event generator allows the simulation of the Drell-Yan-type production processes of hh, h" and H.sup.± in proton-proton collisions at LHC energies. Also the subsequent leptonic decays of these bosons into the μ.sup.+μ.sup.-, μ.sup.+v.sub.μ and μ.sup.- bar.v.sub.μ channels are studied as well as the dominant background processes. We estimate the integrated luminosities needed in pp collisions at center-of-mass energies of 8 and 14 TeV for significant observations of the Higgs bosons hh, h" and H.sup.± in these muonic channels.
Probing TeV gravity with the ATLAS detector Lendermann, Victor; Collaboration, the Atlas
Journal of physics. Conference series,
06/2009, Letnik:
171, Številka:
1
Journal Article
Recenzirano
Odprti dostop
Models with compactified extra space dimensions offer a new way to address outstanding problems in and beyond the Standard Model. In these models, the strength of gravity is strongly increased at ...small distances, which opens up the possibility of observing quantum gravity effects in the TeV energy range reachable by the LHC. One of the most spectacular phenomena would be the production of microscopic black holes. Searches for black holes are foreseen in the ATLAS experiment with the start-up of data taking in 2009. We present feasibility studies for the triggering, selection and reconstruction of the black hole event topologies, the black hole discovery potential and their identification.
QED Compton scattering at HERA is discussed in terms of the information it may reveal on the proton structure at low momentum transfers Q2. Detailed Monte Carlo studies are performed which show that ...the analysis of inelastic QED Compton events allows the extension of present HERA structure function measurements to a kinematic domain, which up to now was only accessed in fixed target data. For these studies an improved version of the COMPTON event generator is used, where special emphasis has been put on modelling the hadronic final state at low invariant masses. As the low Q2 regime is sometimes also discussed in the context of the collinear approximation and the possibility of measuring the photonic content of the proton, the Monte Carlo studies are also used to check the validity of this approach. It is found that the proposed concept of a photon density \(\gamma\) of the proton does not provide sufficient accuracy for the description of inelastic QED Compton scattering.
The ATLAS Level-1 Calorimeter Trigger is one of the main elements of the first stage of event selection for the ATLAS experiment at the LHC. The input stage consists of a mixed analogue/digital ...component taking trigger sums from the ATLAS calorimeters. The trigger logic is performed in a digital, pipelined system with several stages of processing, largely based on FPGAs, which perform programmable algorithms in parallel with a fixed latency to process about 300 Gbyte/s of input data. The real-time output consists of counts of different types of physics objects and energy sums. The production of final modules started in 2006, and installation of these modules and the necessary infrastructure at ATLAS has been underway for some time, with the intention of having a full system in situ during 2007, before first collisions at the LHC. The first experiences of commissioning and running the full scale system will be presented, along with results from integration tests performed with the upstream calorimeters, and the downstream trigger and data flow systems.
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