Search for High-mass Z Gamma Resonances at Sqrt(s)

Search for High-mass Z Gamma Resonances at Sqrt(s)
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Release: 2016
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A search for massive resonances decaying to a Z boson and a photon is performed in events with a hadronically decaying Z boson candidate, separately in light-quark and b quark decay modes, identified using jet substructure and advanced b tagging techniques. Results are based on samples of proton-proton collisions collected with the CMS detector at the LHC at center-of-mass energies of 8 and 13 TeV, corresponding to integrated luminosities of 19.7 and 2.7 inverse femtobarns, respectively. The results of the search are combined with those of a similar search in the leptonic decay modes of the Z boson, based on the same data sets. Spin-0 resonances with various widths and with masses in a range between 0.2 and 3.0 TeV are considered. No significant excess is observed either in the individual analyses or the combination. The results are presented in terms of upper limits on the production cross section of such resonances and constitute the most stringent limits to date for a wide range of masses.

Search for Associated Production of Dark Matter with a Higgs Boson Decaying to $b\bar{b}$ Or $\gamma\gamma$ at $\sqrt{s}$

Search for Associated Production of Dark Matter with a Higgs Boson Decaying to $b\bar{b}$ Or $\gamma\gamma$ at $\sqrt{s}$
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Release: 2017
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A search for dark matter is performed using events with large missing transverse momentum and a Higgs boson decaying either to a pair of bottom quarks or to a pair of photons. The data from proton-proton collisions at a center-of-mass energy of 13 TeV, collected with the CMS detector at the LHC, correspond to an integrated luminosity of 2.3 inverse-femtobarns. Results are interpreted in the context of a Z'-two-Higgs-doublet model, where a high-mass resonance Z' decays into a pseudoscalar boson A and a CP-even scalar Higgs boson, and the A decays to a pair of dark matter particles. No significant excesses are observed over the background prediction. Combining results from the two decay channels yields exclusion limits in the signal cross section in the m[Z']-m[A] phase space. The observed data exclude, for Z' coupling strength g[Z'] = 0.8 and m[A] = 300 GeV for example, the Z' mass range of 600 to 1860 GeV. This is the first result on a search for dark matter produced in association with a Higgs boson that includes constraints on h to gamma-gamma obtained at sqrt(s) = 13 TeV.

LHC Physics

LHC Physics
Author: T. Binoth
Publisher: CRC Press
Total Pages: 415
Release: 2012-04-25
Genre: Science
ISBN: 1439837708

Exploring the phenomenology of the Large Hadron Collider (LHC) at CERN, LHC Physics focuses on the first years of data collected at the LHC as well as the experimental and theoretical tools involved. It discusses a broad spectrum of experimental and theoretical activity in particle physics, from the searches for the Higgs boson and physics beyond the Standard Model to studies of quantum chromodynamics, the B-physics sector, and the properties of dense hadronic matter in heavy-ion collisions. Covering the topics in a pedagogical manner, the book introduces the theoretical and phenomenological framework of hadron collisions and presents the current theoretical models of frontier physics. It offers overviews of the main detector components, the initial calibration procedures, and search strategies. The authors also provide explicit examples of physics analyses drawn from the recently shut down Tevatron. In the coming years, or perhaps even sooner, the LHC experiments may reveal the Higgs boson and offer insight beyond the Standard Model. Written by some of the most prominent and active researchers in particle physics, this volume equips new physicists with the theory and tools needed to understand the various LHC experiments and prepares them to make future contributions to the field.

We Have No Idea

We Have No Idea
Author: Jorge Cham
Publisher: Penguin
Total Pages: 369
Release: 2018-05-08
Genre: Science
ISBN: 0735211523

Prepare to learn everything we still don’t know about our strange and mysterious universe Humanity's understanding of the physical world is full of gaps. Not tiny little gaps you can safely ignore —there are huge yawning voids in our basic notions of how the world works. PHD Comics creator Jorge Cham and particle physicist Daniel Whiteson have teamed up to explore everything we don't know about the universe: the enormous holes in our knowledge of the cosmos. Armed with their popular infographics, cartoons, and unusually entertaining and lucid explanations of science, they give us the best answers currently available for a lot of questions that are still perplexing scientists, including: * Why does the universe have a speed limit? * Why aren't we all made of antimatter? * What (or who) is attacking Earth with tiny, superfast particles? * What is dark matter, and why does it keep ignoring us? It turns out the universe is full of weird things that don't make any sense. But Cham and Whiteson make a compelling case that the questions we can't answer are as interesting as the ones we can. This fully illustrated introduction to the biggest mysteries in physics also helpfully demystifies many complicated things we do know about, from quarks and neutrinos to gravitational waves and exploding black holes. With equal doses of humor and delight, Cham and Whiteson invite us to see the universe as a possibly boundless expanse of uncharted territory that's still ours to explore.