76 research outputs found
B-physics Potential Of The Atlas Experiment, And, Performance Of The Atlas Transition Radiation Tracker
No full textThe ATLAS experiment is one of the four experiments at the Large Hadron Collider (LHC), which is supposed to be operational in early 2007. Proton-proton collisions at an unprecedented centre-of-mass energy of 14 TeV will probe new frontiers of the universe, hopefully providing a better understanding of the laws governing our universe. Although the ATLAS detector has been optimized to search for the Higgs boson within the full mass range expected and other new particles, it is well adapted to cover a wide range of B-physics topics. The determination of the angles of the Unitarity Triangle, and measurements of the CP violation are also a key point for a full and coherent understanding of the fundamental forces governing the universe. Intriguing particles, such as the Bc meson, provide a very interesting case to study the interplay of strong and weak interactions, a key problem in the theoretical analysis of the weak decays of hadrons. The Transition Radiation Tracker (TRT) is a combined straw drift tube and transition radiation detector. It provides a combination of continuous tracking with many projective measurements based on individual drift tubes and of a powerful electron identification based on radiator fibers or foils interleaved between the straws. An extensive programme of tests undertaken on several small scale prototypes has shown a good and satisfactory performance
Physics potential of the decays Bs;d -> J/psi eta and Bs -> J/psi phi in the ATLAS experiment at the LHC
No full textThe CP asymmetry predicted by the Standard Model in the decay modes Bs;d -> J/psi eta and Bs -> J/psi phi is very small, and the observation of a sizeable e ect would be a clear indication of new physics beyond the Standard Model. Contrary to the final state J/psi phi, the former final state is a CP eigenstate, and therefore complex angular distribution analyses are not necessary for the asymmetry measurement. In this paper, the approaches for the study of these two decay channels are presented.The CP asymmetry predicted by the Standard Model in the decay modes Bs;d -> J/psi eta and Bs -> J/psi phi is very small, and the observation of a sizeable e ect would be a clear indication of new physics beyond the Standard Model. Contrary to the final state J/psi phi, the former final state is a CP eigenstate, and therefore complex angular distribution analyses are not necessary for the asymmetry measurement. In this paper, the approaches for the study of these two decay channels are presented
separation using the Time over Threshold method in the ATLAS Transition Radiation Tracker
No full textThe e/pi separation performance of the ATLAS Transition Radiation Tracker (TRT) by means of the Time over Threshold method is reported in this note
BCVEGPY: an event generator for hadronic production of the B-c meson
No full textWe have written a Fortran program BCVEGPY, which is an event generator for the hadronic production of the B-c meson through the dominant hard subprocess gg --> B-c(B-c(*)) + b + c. To achieve a compact program, we have written the amplitude of the subprocess with the particle helicity technique and made it as symmetric as possible, by decomposing the gluon self couplings and then applying the symmetries. To check the program, various cross sections of the subprocess have been computed numerically and compared with those in the literature. BCVEGPY is written in a PYTHIA-compatible format, thus it is easy to implement in PYTHIA
Evidence for the decay B+c→J/ψ3π+2π−
No full textEvidence is presented for the decay B+c → J/ψ 3π+2π− using proton-proton collision data, corresponding to an integrated luminosity of 3 fb−1, collected with the LHCb detector. A signal yield of 32 ± 8 decays is found with a significance of 4.5 standard deviations. The ratio of the branching fraction of the B+c → J/ψ3π+2π− decay to that of the B+c → J/ψ π+ decay is measured to be
B(B+c → J/ψ 3π+2π−)/B(B+c → J/ψ π+� = 1.74 ± 0.44 ± 0.24
where the first uncertainty is statistical and the second is systematic
Search for at LHC with the ATLAS detector
No full textThe possibility to detect the Z' boson in the channel Z' -> WW -> enujj with the ATLAS detector is studied in the framework of the Sequential Standard Model. After central cuts optimisation and a study of the jet veto efficiency, the discovery potential of this channel which can help to study the nature of symmetry breaking is estimated at high and low luminosity
Observation potential of the decays in the ATLAS experiment at the LHC
No full textThe observation potential of the decays with the ATLAS detector at the LHC is described in this paper. At present there exist only upper limits for the branching fractions, but at LHC, a clear signal for the decay mode is expected. The branching fraction of this decay mode can thus be measured, and other parameters such as lifetime can be measured as well The decay mode is analogous to the mode , which has been studied extensively in view of CP violation measurements. In these two decay modes, the C asymmetry predicted by the Standard Model is very small, and the observation of a sizeable effect would be a signal of physics beyond the Standard Model. The decay mode constitutes thus a cross-check for the mode . Furthermore, the former final state is a CP-eigenstate and no angular analysis is thus needed. The reconstruction of \etasmesons at LHC experiments has not been addressed before, and therefore the study presented here can also be regarded as an example of the physics prospects with \etasmesons at the LHC
Ultrafast laser-wire scanning with electro-optics
No full textThe possibility is presented of using electro-optics techniques to increase laser-wire scanning rates for intra-train scanning at the international linear collider (ILC). The requirements include the preservation of the laser beam mode quality and the ability to work with laser beam powers of order 10 MW. The first ideas of a possible device configuration are presented together with a survey of Electro-Optic (EO) materials and first experimental results using linear prisms
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