Cosmic strings are topological defects which can be formed in grand unified theory scale phase transitions in the early universe. They are also predicted to form in the context of string theory. The main mechanism for a network of Nambu-Goto cosmic strings to lose energy is through the production of loops and the subsequent emission of gravitational waves, thus offering an experimental signature for the existence of cosmic strings. Here we report on the analysis conducted to specifically search for gravitational-wave bursts from cosmic string loops in the data of Advanced LIGO 2015-2016 observing run (O1). No evidence of such signals was found in the data, and as a result we set upper limits on the cosmic string parameters for three recent loop distribution models. In this paper, we initially derive constraints on the string tension Gμ and the intercommutation probability, using not only the burst analysis performed on the O1 data set but also results from the previously published LIGO stochastic O1 analysis, pulsar timing arrays, cosmic microwave background and big-bang nucleosynthesis experiments. We show that these data sets are complementary in that they probe gravitational waves produced by cosmic string loops during very different epochs. Finally, we show that the data sets exclude large parts of the parameter space of the three loop distribution models we consider.
The WZ production cross section is measured in proton-proton collisions at a centreof-mass energy √ s = 13 TeV using data collected with the CMS detector, corresponding to an integrated luminosity of 35.9 fb −1 . The inclusive cross section is measured to be σ tot (pp → WZ) = 48.09 +1.00 −0.96 (stat) +0.44 −0.37 (theo) +2.39 −2.17 (syst) ± 1.39 (lumi) pb, resulting in a total uncertainty of −2.78/+2.98 pb. Fiducial cross section and ratios of chargedependent cross section measurements are provided. Differential cross section measurements are also presented with respect to three variables: the Z boson transverse momentum p T , the leading jet p T , and the M(WZ) variable, defined as the invariant mass of the system composed of the three leptons and the missing transverse momentum. Differential measurements with respect to the W boson p T , separated by charge, are also shown. Results are consistent with standard model predictions, favouring next-to-next-to-leading-order predictions over those at next-to-leading order. Constraints on anomalous triple gauge couplings are derived via a binned maximum likelihood fit to the M(WZ) variable.
We present measurements of the B ϩ meson total cross section and differential cross section d/dp T . The measurements use a 98Ϯ4 pb Ϫ1 sample of pp collisions at ͱsϭ1.8 TeV collected by the CDF detector.Charged B meson candidates are reconstructed through the decay B Ϯ →J/K Ϯ with J/→ ϩ Ϫ . The total cross section, measured in the central rapidity region ͉y͉Ͻ1.0 for p T (B)Ͼ6.0 GeV/c, is 3.6Ϯ0.6(stat syst) b. The measured differential cross section is substantially larger than typical QCD predictions calculated to next-to-leading order.
We study the Lund-Regge equation that governs the motion of strings in a constant background antisymmetric tensor field by using the duality between the Lund-Regge equation and the complex sine-Gordon equation. Similar to the cases of vortex filament configurations in fluid dynamics, we find various exact solitonic string configurations which are the analogue of the Kelvin wave, the Hasimoto soliton and the smoke ring. In particular, using the duality relation, we obtain a completely new type of configuration which corresponds to the breather of the complex sine-Gordon equation.
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