We consider the production at the LHC of exotic quarks U+ of charge Q=+(5/3)e and D− of charge Q=−(4/3)e of mass m* arising in a composite fermion scenario characterized by a compositeness scale Λ. ...Such states are predicted in composite models of higher isospin multiplets (IW=1 or IW=3/2). Given their exotic charges (such as 5/3), their decays proceed through the electroweak interactions. We compute decay widths and rates for resonant production of the exotic quarks at the LHC. Partly motivated by the recent observation of an excess by the CMS collaboration in the epTjj final state signature we focus on pp→U+j→W++jj→ℓ+pTjj and then perform a fast simulation of the detector reconstruction based on Delphes. We then scan the parameter space of the model (m*=Λ) and study the statistical significance of the signal against the relevant standard model background (Wjj followed by leptonic decay of the W gauge boson) providing the luminosity curves as function of m* for discovery at 3- and 5−σ level.
Here we describe a novel application of the end-to-end deep learning technique to the task of discriminating top quark-initiated jets from those originating from the hadronization of a light quark or ...a gluon. The end-to-end deep learning technique uses low-level detector representation of high-energy collision event as inputs to deep learning algorithms. In this study, we use low-level detector information from the simulated Compact Muon Solenoid (CMS) open data samples to construct the top jet classifiers. To optimize classifier performance we progressively add low-level information from the CMS tracking detector, including pixel detector reconstructed hits and impact parameters, and demonstrate the value of additional tracking information even when no new spatial structures are added. Relying only on calorimeter energy deposits and reconstructed pixel detector hits, the end-to-end classifier achieves an area under the receiver operator curve (AUC) score of 0.975 ± 0.002 for the task of classifying boosted top quark jets. After adding derived track quantities, the classifier AUC score increases to 0.9824 ± 0.0013, serving as the first performance benchmark for these CMS open data samples.
We combine searches by the CDF and D0 Collaborations for the associated production of a Higgs boson with a W or Z boson and subsequent decay of the Higgs boson to a bottom-antibottom quark pair. The ...data, originating from Fermilab Tevatron pp collisions at √s = 1.96 TeV, correspond to integrated luminosities of up to 9.7 fb(-1). The searches are conducted for a Higgs boson with mass in the range 100-150 GeV/c(2). We observe an excess of events in the data compared with the background predictions, which is most significant in the mass range between 120 and 135 GeV/c(2). The largest local significance is 3.3 standard deviations, corresponding to a global significance of 3.1 standard deviations. We interpret this as evidence for the presence of a new particle consistent with the standard model Higgs boson, which is produced in association with a weak vector boson and decays to a bottom-antibottom quark pair.
Higgs boson studies at the Tevatron Agnew, J. P.; Annovi, A.; Bandurin, D. V. ...
Physical review. D, Particles, fields, gravitation, and cosmology,
09/2013, Letnik:
88, Številka:
5
Journal Article
Recenzirano
Odprti dostop
We combine searches by the CDF and DO Collaborations for the standard model Higgs boson with mass in the range 90- 200 GeV /c super(2) produced in the gluon-gluon fusion, WH, ZH, ttH, and vector ...boson fusion processes, and decaying in the H arrow right bb, H arrow right W super(+)W super(-), H arrow right ZZ, H arrow right tau super(+)tau super(-), and H arrow right gamma gamma modes. The data correspond to integrated luminosities of up to 10 fb super(-1) and were collected at the Fermilab Tevatron in pp collisions at radicals = 1.96 TeV. The searches are also interpreted in the context of fermiophobic and fourth generation models. We observe a significant excess of events in the mass range between 115 and 140 GeV /c super(2). The local significance corresponds to 3.0 standard deviations at mH = 125 GeV /c super(2), consistent with the mass of the Higgs boson observed at the LHC, and we expect a local significance of 1.9 standard deviations. We separately combine searches for H arrow right bb, H arrow right W super(+)W super(-), H arrow right tau super(+)t super(-), and H arrow right gamma gamma . The observed signal strengths in all channels are consistent with the presence of a standard model Higgs boson with a mass of 125 GeV /c super(2).
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