Symmetry breaking in (gravitating) scalar field models describing interacting boson stars and Q-balls

We investigate the properties of interacting Q-balls and boson stars that sit on top of each other in great detail. The model that describes these solutions is essentially a (gravitating) two-scalar field model where both scalar fields are complex. We construct interacting Q-balls or boson stars with arbitrarily small charges but finite mass. We observe that in the interacting case - where the interaction can be either due to the potential or due to gravity - two types of solutions exist for equal frequencies: one for which the two scalar fields are equal, but also one for which the two scalar fields differ. This constitutes a symmetry breaking in the model. While for Q-balls asymmetric solutions have always corresponding symmetric solutions and are thus likely unstable to decay to symmetric solutions with lower energy, there exists a parameter regime for interacting boson stars, where only asymmetric solutions exist. We present the domain of existence for two interacting non-rotating solutions as well as for solutions describing the interaction between rotating and non-rotating Q-balls and boson stars, respectively.Comment: 33 pages including 21 figures; v2: version considerably extended: 6 new figures added, equations of motion added, discussion on varying gravitational coupling added, references adde

Symmetry breaking in (gravitating) scalar field models describing interacting boson stars and Q-balls

peer reviewedWe investigate the properties of interacting Q-balls and boson stars that sit on top of each other in great detail. The model that describes these solutions is essentially a (gravitating) two-scalar field model where both scalar fields are complex. We construct interacting Q-balls or boson stars with arbitrarily small charges but finite mass. We observe that in the interacting case-where the interaction can be either due to the potential or due to gravity-two types of solutions exist for equal frequencies: one for which the two-scalar fields are equal, but also one for which the two-scalar fields differ. This constitutes a symmetry breaking in the model. While for Q-balls asymmetric solutions have always corresponding symmetric solutions and are thus likely unstable to decay to symmetric solutions with lower energy, there exists a parameter regime for interacting boson stars, where only asymmetric solutions exist. We present the domain of existence for two interacting nonrotating solutions as well as for solutions describing the interaction between rotating and nonrotating Q-balls and boson stars, respectively

Search for Dijet Resonances in 7 TeV pp Collisions at CMS

peer reviewedA search for narrow resonances in the dijet mass spectrum is performed using data corresponding to an integrated luminosity of 2.9 inverse pb collected by the CMS experiment at the LHC. Upper limits at the 95% confidence level (CL) are presented on the product of the resonance cross section, branching fraction into dijets, and acceptance, separately for decays into quark-quark, quark-gluon, or gluon-gluon pairs. The data exclude new particles predicted in the following models at the 95% CL: string resonances, with mass less than 2.50 TeV, excited quarks, with mass less than 1.58 TeV, and axigluons, colorons, and E_6 diquarks, in specific mass intervals. This extends previously published limits on these models

Measurement of the charge ratio of atmospheric muons with the CMS detector

peer reviewedWe present a measurement of the ratio of positive to negative muon fluxes from cosmic ray interactions in the atmosphere, using data collected by the CMS detector both at ground level and in the underground experimental cavern at the CERN LHC. Muons were detected in the momentum range from 5 GeV/c to 1 TeV/c. The surface flux ratio is measured to be 1.2766 \pm 0.0032(stat.) \pm 0.0032 (syst.), independent of the muon momentum, below 100 GeV/c. This is the most precise measurement to date. At higher momenta the data are consistent with an increase of the charge ratio, in agreement with cosmic ray shower models and compatible with previous measurements by deep-underground experiments

Transverse-Momentum and Pseudorapidity Distributions of Charged Hadrons in pp Collisions at sqrt(s)=7 TeV.

peer reviewe

Search for W' --> tb in proton-proton collisions at sqrt(s) = 8 TeV

peer reviewe

P-type Silicon Strip Sensors for the new CMS tracker at HL-LHC

peer reviewedParticules élém. et astropart. (exp.) - Fédération Wallonie Bruxelle

Characterisation of irradiated thin silicon sensors for the CMS phase II pixel upgrade.

peer reviewedParticules élém. et astropart. (exp.) - Fédération Wallonie Bruxelle

Search for a massive resonance decaying into a Higgs boson and a W or Z boson in hadronic final states in proton-proton collisions at sqrt(s) = 8 TeV

peer reviewe

First Measurement of Bose-Einstein Correlations in proton-Proton Collisions at sqrt(s) = 0.9 and 2.36 TeV at the LHC

peer reviewe