Production of a Z Boson and Two Jets with One Heavy-quark Tag PDF Download
Are you looking for read ebook online? Search for your book and save it on your Kindle device, PC, phones or tablets. Download Production of a Z Boson and Two Jets with One Heavy-quark Tag PDF full book. Access full book title Production of a Z Boson and Two Jets with One Heavy-quark Tag by . Download full books in PDF and EPUB format.
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 11
Get Book Here
Book Description
We present a next-to-leading-order calculation of the production of a Z boson with two jets, one or more of which contains a heavy quark (Q = c, b). We show that the cross section with only one heavy-quark jet is larger than that with two heavy-quark jets at both the Fermilab Tevatron and the CERN LHC. These processes are the dominant irreducible backgrounds to a Higgs boson produced in association with a Z boson, followed by h --> b{bar b}. Our calculation makes use of a heavy-quark distribution function, which resums collinear logarithms and makes the next-to-leading-order calculation tractable.
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 11
Get Book Here
Book Description
We present a next-to-leading-order calculation of the production of a Z boson with two jets, one or more of which contains a heavy quark (Q = c, b). We show that the cross section with only one heavy-quark jet is larger than that with two heavy-quark jets at both the Fermilab Tevatron and the CERN LHC. These processes are the dominant irreducible backgrounds to a Higgs boson produced in association with a Z boson, followed by h --> b{bar b}. Our calculation makes use of a heavy-quark distribution function, which resums collinear logarithms and makes the next-to-leading-order calculation tractable.
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 14
Get Book Here
Book Description
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 188
Get Book Here
Book Description
The dominant background in searches for a Higgs boson decaying into b-quarks at the Tevatron is production of a Z boson in association with either b- or c-quark initiated jets (b or c jets). This thesis describes the first measurements of the ratio of differential cross sections [sigma] (Z + b jet)/ [sigma](Z + jet), and the first measurements of the ratio of cross sections [sigma] (Z + c jet)/ [sigma](Z + jet) and [sigma] (Z + c jet)/ [sigma](Z + b jet). These measurements are performed using the full D0 Run II data set corresponding to an integrated luminosity of 9.7 fb-1. The ratio of differential cross sections [sigma](Z + b jet)/[sigma] (Z + jet) have been measured as a function of jet and Z boson pT, jet [eta], and [Delta][phi](Z, jet). The Z+c jet ratios of differential cross sections are measured as a function of jet and Z boson pT.
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages :
Get Book Here
Book Description
Measurements of the associated production of a Z boson with at least one jet originating from a b quark in proton-proton collisions at $\sqrt{s}$ = 8 TeV are presented. Differential cross sections are measured with data collected by the CMS experiment corresponding to an integrated luminosity of 19.8 inverse femtobarns. Z bosons are reconstructed through their decays to electrons and muons. Cross sections are measured as a function of observables characterizing the kinematics of the b jet and the Z boson. Ratios of differential cross sections for the associated production with at least one b jet to the associated production with any jet are also presented. The production of a Z boson with two b jets is investigated, and differential cross sections are measured for the dijet system. Results are compared to theoretical predictions, testing two different flavour schemes for the choice of initial-state partons.
Author: Simone Marzani
Publisher: Springer
ISBN: 3030157091
Category : Science
Languages : en
Pages : 205
Get Book Here
Book Description
This concise primer reviews the latest developments in the field of jets. Jets are collinear sprays of hadrons produced in very high-energy collisions, e.g. at the LHC or at a future hadron collider. They are essential to and ubiquitous in experimental analyses, making their study crucial. At present LHC energies and beyond, massive particles around the electroweak scale are frequently produced with transverse momenta that are much larger than their mass, i.e., boosted. The decay products of such boosted massive objects tend to occupy only a relatively small and confined area of the detector and are observed as a single jet. Jets hence arise from many different sources and it is important to be able to distinguish the rare events with boosted resonances from the large backgrounds originating from Quantum Chromodynamics (QCD). This requires familiarity with the internal properties of jets, such as their different radiation patterns, a field broadly known as jet substructure. This set of notes begins by providing a phenomenological motivation, explaining why the study of jets and their substructure is of particular importance for the current and future program of the LHC, followed by a brief but insightful introduction to QCD and to hadron-collider phenomenology. The next section introduces jets as complex objects constructed from a sequential recombination algorithm. In this context some experimental aspects are also reviewed. Since jet substructure calculations are multi-scale problems that call for all-order treatments (resummations), the bases of such calculations are discussed for simple jet quantities. With these QCD and jet physics ingredients in hand, readers can then dig into jet substructure itself. Accordingly, these notes first highlight the main concepts behind substructure techniques and introduce a list of the main jet substructure tools that have been used over the past decade. Analytic calculations are then provided for several families of tools, the goal being to identify their key characteristics. In closing, the book provides an overview of LHC searches and measurements where jet substructure techniques are used, reviews the main take-home messages, and outlines future perspectives.
Author: Calvin S. Kalman
Publisher:
ISBN:
Category : Baryons
Languages : en
Pages : 352
Get Book Here
Book Description
Author:
Publisher:
ISBN:
Category : Hadrons
Languages : en
Pages : 368
Get Book Here
Book Description
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 162
Get Book Here
Book Description
The search for the production of the Standard Model Z boson in association with a W boson is motivated and discussed. This is performed using 4.3 fb−1 of Tevatron Run II data collected with the CDF detector in (square root)s = 1.96 TeV proton anti-proton collisions. This is a signature-based analysis where the W boson decays semileptonically into a high-P{sub T} electron or muon plus a neutrino, and where the Z boson decays into two b quark jets (b-jets). We increase the signal-to-background ratio by identifying the b-quarks in the jets with a new neural network-based algorithm. Another neural network then uses kinematic information to distinguish WZ to further increase the signal-to-background ratio. Since our sensitivity is still not enough to achieve an observation, we set a 95% Confidence Level upper limit on the product of the WZ production cross section and its branching fraction to the decay products specified above, and express it as a ratio to the theoretical Standard Model prediction. The resulting limit is 3.9 x SM (3.9 x SM expected).
Author: Christian Gütschow
Publisher:
ISBN:
Category :
Languages : en
Pages : 0
Get Book Here
Book Description
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 127
Get Book Here
Book Description
This study presents the measurement of the rapidity distributions in events containing a Z boson and a jet in proton-proton collisions at a center-of-mass energy of 7 TeV. The data correspond to an integrated luminosity of approximately 5 fb-11, recorded by the CMS detector at the Large Hadron Collider (LHC). The measured angular distributions are compared with the predictions from next-to-leading order perturbative QCD calculations and two generator programs that combine tree-level matrix element calculations with parton showers. We also present a measurement of jet production rates in association with a Z boson using data recorded at a center-of-mass energy of 8 TeV and with an integrated luminosity of 19.8 fb-1. This measurement provides a stringent test of perturbative QCD calculations, and the result is compared with predictions from theoretical calculations.
