Página 1 dos resultados de 3740 itens digitais encontrados em 0.014 segundos
- Springer Berlin Heidelberg
- University of Rochester
- American Physical Soc
- Universidade de Cantabria
- Universidade Cornell
- [Barcelona] : Universitat Autònoma de Barcelona,
- University of Cambridge; Department of Physics; Wolfson College; CERN; Cavendish Laboratory
- Elsevier
- American Physical Society
- Mais Publicadores...
Measurement of the electroweak production of dijets in association with a Z-boson and distributions sensitive to vector boson fusion in proton-proton collisions at s√= 8 TeV using the ATLAS detector
Fonte: Springer Berlin Heidelberg
Publicador: Springer Berlin Heidelberg
Tipo: Artigo de Revista Científica
Publicado em //2014
ENG
Relevância na Pesquisa
46.31%
Measurements of fiducial cross sections for the electroweak production of two jets in association with a Z-boson are presented. The measurements are performed using 20.3 fb−1 of proton-proton collision data collected at a centre-of-mass energy of s√ = 8 TeV by the ATLAS experiment at the Large Hadron Collider. The electroweak component is extracted by a fit to the dijet invariant mass distribution in a fiducial region chosen to enhance the electroweak contribution over the dominant background in which the jets are produced via the strong interaction. The electroweak cross sections measured in two fiducial regions are in good agreement with the Standard Model expectations and the background-only hypothesis is rejected with significance above the 5σ level. The electroweak process includes the vector boson fusion production of a Z-boson and the data are used to place limits on anomalous triple gauge boson couplings. In addition, measurements of cross sections and differential distributions for inclusive Z-boson-plus-dijet production are performed in five fiducial regions, each with different sensitivity to the electroweak contribution. The results are corrected for detector effects and compared to predictions from the Sherpa and Powheg event generators.
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Measurement of differential production cross-sections for a Z boson in association with b-jets in 7 TeV proton-proton collisions with the ATLAS detector
Fonte: Springer Berlin Heidelberg
Publicador: Springer Berlin Heidelberg
Tipo: Artigo de Revista Científica
Publicado em //2014
ENG
Relevância na Pesquisa
46.33%
Measurements of differential production cross-sections of a Z boson in association
with b-jets in pp collisions at √
s = 7 TeV are reported. The data analysed correspond
to an integrated luminosity of 4.6 fb−1
recorded with the ATLAS detector at the Large
Hadron Collider. Particle-level cross-sections are determined for events with a Z boson
decaying into an electron or muon pair, and containing b-jets. For events with at least one
b-jet, the cross-section is presented as a function of the Z boson transverse momentum and
rapidity, together with the inclusive b-jet cross-section as a function of b-jet transverse momentum,
rapidity and angular separations between the b-jet and the Z boson. For events
with at least two b-jets, the cross-section is determined as a function of the invariant mass
and angular separation of the two highest transverse momentum b-jets, and as a function
of the Z boson transverse momentum and rapidity. Results are compared to leading-order
and next-to-leading-order perturbative QCD calculations.
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A measurement of the Z forward-backward charge asymmetry in proton-antiproton decaying to electron-positron
Fonte: University of Rochester
Publicador: University of Rochester
Tipo: Tese de Doutorado
Formato: Number of Pages:125
ENG
Relevância na Pesquisa
56.12%
Thesis (Ph. D.)--University of Rochester. Dept. of Physics and Astronomy, 2006.; We present a measurement of the Z boson forward-backward charge asymmetry of the process pp¯ [arrow right] [gamma]*/ Z + X [arrow right] e + e - + X , where the mass of the intermediate [gamma]*/ Z has invariant mass above 30 GeV/c 2 . The measurement uses 0.36 fb -1 of Run II data. The method of matrix inversion is used to correct for the distortion in the measurement caused by the detector resolution and photon radiation in the final state. A search for a new physics based upon the forward-backward asymmetry is also presented.
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Measurement of Z boson production in Pb-Pb collisions at √(s(NN))=2.76 TeV with the ATLAS detector; Measurement of Z boson production in Pb-Pb collisions at root(s(NN))=2.76 TeV with the ATLAS detector
Fonte: American Physical Soc
Publicador: American Physical Soc
Tipo: Artigo de Revista Científica
Publicado em //2013
EN
Relevância na Pesquisa
46.31%
The ATLAS experiment has observed 1995 Z boson candidates in data corresponding to 0.15 nb⁻¹ of integrated luminosity obtained in the 2011 LHC Pb+Pb run at √(s(N)(N))= 2.76 TeV. The Z bosons are reconstructed via dielectron and dimuon decay channels, with a background contamination of less than 3%. Results from the two channels are consistent and are combined. Within the statistical and systematic uncertainties, the per-event Z boson yield is proportional to the number of binary collisions estimated by the Glauber model. The elliptic anisotropy of the azimuthal distribution of the Z boson with respect to the event plane is found to be consistent with zero.; G. Aad ... P. Jackson ... et al. (ATLAS Collaboration)
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Medida de la sección eficaz de producción del bosón Z en el experimento CMS del LHC
Fonte: Universidade de Cantabria
Publicador: Universidade de Cantabria
Tipo: Trabalho de Conclusão de Curso
SPA
Relevância na Pesquisa
46.32%
#Bosón Z#Solenoide compacto de muones#Gran colisionador de hadrones#Compact muon solenoid (CMS)#Large hadron collider (LHC)
En este trabajo se presenta el análisis llevado a cabo para la medida del valor de la sección eficaz de producción del bosón Z (σz), boson “gauge” portador de la corriente neutra de la fuerza electrodébil, a una energía de √s=8 TeV (centro de masas). Para ello se ha utilizado una luminosidad integrada de 5.3 fb-1 de datos recogidos por el detector Compact Muon Solenoid (CMS), situado en el colisionador de hadrones LHC del laboratorio CERN (Ginebra, Suiza).
Los resultados obtenidos de la sección eficaz de producción del bosón Z para estos dos canales son:
σ(z→e+e-)=1.125±0.001(stat)±0.013(sys)±0.050(lumi) nb
σ(z→μ+μ-)=1.162±0.001(stat)±0.026(sys)±0.051(lumi) nb
los cuales son compatibles con los valores predichos por el ME y con los valores obtenidos de manera oficial por la colaboración CMS.; Grado en Física
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A note on the rare decay of a Higgs boson into photons and a $Z$ boson
Fonte: Universidade Cornell
Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 10/11/2004
Relevância na Pesquisa
46.36%
We have calculated the width of the rare decay $H\to\gamma\gamma Z$ at
one-loop level in the standard model for Higgs boson masses in the range $115
{\rm GeV} \leq m_H \leq 160 {\rm GeV}$ . For this range of Higgs boson masses
we find that $Z$ boson is predominantly longitudinally polarized, and the
photons have the same helicity. A comparison of the decay width $\Gamma(H\to
\gamma\gamma Z)$ to those of $H\to\gamma\gamma$ and $H\to\gamma Z$ shows that,
for the Higgs boson mass of $m_H \sim 135 \rm{GeV}$, the ratios of the decay
widths are $\Gamma(H\to\gamma\gamma Z) / \Gamma(H\to\gamma\gamma) \sim
\Gamma(H\to\gamma\gamma Z) / \Gamma(H\to\gamma Z) \sim 10^{-5}-10^{-6}$.; Comment: 4 pages, 5 figures, RevTeX
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Measurement of the forward $Z$ boson production cross-section in $pp$ collisions at $\sqrt{s}$ = 7 TeV
Fonte: Universidade Cornell
Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
56.22%
A measurement of the production cross-section for $Z$ bosons that decay to
muons is presented. The data were recorded by the LHCb detector during $pp$
collisions at a centre-of-mass energy of 7 TeV, and correspond to an integrated
luminosity of 1.0 fb$^{-1}$. The cross-section is measured for muons in the
pseudorapidity range $2.0 < \eta < 4.5$ with transverse momenta $p_{T} > 20$
GeV/c. The dimuon mass is restricted to $60 < M_{\mu^{+}\mu^{-}} < 120$
GeV/c$^{2}$. The measured cross-section is
$$\sigma_{Z\rightarrow\mu^{+}\mu^{-}} = (76.0 \pm 0.3 \pm 0.5 \pm 1.0 \pm 1.3)
\, \text{pb}$$ where the uncertainties are due to the sample size, systematic
effects, the beam energy and the luminosity. This result is in good agreement
with theoretical predictions at next-to-next-to-leading order in perturbative
quantum chromodynamics. The cross-section is also measured differentially as a
function of kinematic variables of the $Z$ boson. Ratios of the production
cross-sections of electroweak bosons are presented using updated LHCb
measurements of $W$ boson production. A precise test of the Standard Model is
provided by the measurement of the ratio
$$\frac{\sigma_{W^{+}\rightarrow\mu^{+}\nu_{\mu}} +
\sigma_{W^{-}\rightarrow\mu^{-}\bar{\nu}_{\mu}}}{\sigma_{Z\rightarrow\mu^{+}\mu^{-}}}
= 20.63\pm0.09\pm0.12\pm0.05...
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Measurement of forward $W$ and $Z$ boson production in $pp$ collisions at $\sqrt{s} = 8\mathrm{\,Te\kern -0.1em V}$
Fonte: Universidade Cornell
Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 25/11/2015
Relevância na Pesquisa
56.27%
Measurements are presented of electroweak boson production using data from
$pp$ collisions at a centre-of-mass energy of $\sqrt{s} = 8\mathrm{\,Te\kern
-0.1em V}$. The analysis is based on an integrated luminosity of
$2.0\mathrm{\,fb}^{-1}$ recorded with the LHCb detector. The bosons are
identified in the $W\rightarrow\mu\nu$ and $Z\rightarrow\mu^{+}\mu^{-}$ decay
channels. The cross-sections are measured for muons in the pseudorapidity range
$2.0 < \eta < 4.5$, with transverse momenta $p_{\rm T} > 20{\mathrm{\,Ge\kern
-0.1em V\!/}c}$ and, in the case of the $Z$ boson, a dimuon mass within $60 <
M_{\mu^{+}\mu^{-}} < 120{\mathrm{\,Ge\kern -0.1em V\!/}c^{2}}$. The results are
\begin{align*} \sigma_{W^{+}\rightarrow\mu^{+}\nu} &= 1093.6 \pm 2.1 \pm 7.2
\pm 10.9 \pm 12.7{\rm \,pb} \, ,\\
\sigma_{W^{-}\rightarrow\mu^{-}\overline{\nu}} &= \phantom{0}818.4 \pm 1.9 \pm
5.0 \pm \phantom{0}7.0 \pm \phantom{0}9.5{\rm \,pb} \, ,\\
\sigma_{Z\rightarrow\mu^{+}\mu^{-}} &= \phantom{00}95.0 \pm 0.3 \pm 0.7 \pm
\phantom{0}1.1 \pm \phantom{0}1.1{\rm \,pb} \, , \end{align*} where the first
uncertainties are statistical, the second are systematic, the third are due to
the knowledge of the LHC beam energy and the fourth are due to the luminosity
determination. The evolution of the $W$ and $Z$ boson cross-sections with
centre-of-mass energy is studied using previously reported measurements with
$1.0\mathrm{\...
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Measurement of differential production cross-sections for a $Z$ boson in association with $b$-jets in 7 TeV proton-proton collisions with the ATLAS detector
Fonte: Universidade Cornell
Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
46.33%
Measurements of differential production cross-sections of a $Z$ boson in
association with $b$-jets in $pp$ collisions at $\sqrt{s}=7$ TeV are reported.
The data analysed correspond to an integrated luminosity of 4.6 fb$^{-1}$
recorded with the ATLAS detector at the Large Hadron Collider. Particle-level
cross-sections are determined for events with a $Z$ boson decaying into an
electron or muon pair, and containing $b$-jets. For events with at least one
$b$-jet, the cross-section is presented as a function of the $Z$ boson
transverse momentum and rapidity, together with the inclusive $b$-jet
cross-section as a function of $b$-jet transverse momentum, rapidity and
angular separations between the $b$-jet and the $Z$ boson. For events with at
least two $b$-jets, the cross-section is determined as a function of the
invariant mass and angular separation of the two highest transverse momentum
$b$-jets, and as a function of the $Z$ boson transverse momentum and rapidity.
Results are compared to leading-order and next-to-leading-order perturbative
QCD calculations.; Comment: 34 pages plus author list and cover pages (57 pages total), 13
figures, 4 tables, published in JHEP10(2014)141. All figures including
auxiliary figures are available at
http://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/STDM-2012-15/
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Lepton flavor violating $Z$-boson couplings from non-standard Higgs interactions
Fonte: Universidade Cornell
Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 12/07/2015
Relevância na Pesquisa
46.38%
The Standard Model predicts that the Higgs boson couples to the fermions in
the mass eigenstates. We consider the effects of lepton flavor violating (LFV)
$Z$ boson couplings in the case where the Higgs boson has flavor non-diagonal
Yukawa interactions with the muon and the tau lepton generated from physics
beyond the Standard Model. We list the formulae of the couplings of the
effective interactions among the $\tau$ lepton, the muon and the $Z$ boson.
Using these formulae, we calculate the branching fractions of various
leptonic and hadronic LFV $\tau$ decays, and the LFV $Z$ boson decay: $Z\to
\tau\mu$. Although the $Z$-boson contributions to LFV tau decays cannot be
ignored in terms of the counting of operator dimensions or chirality
flipptings, it turns out that they are not very significant for $\tau\to3\mu$
and $\tau\to\mu\rho$ decays. We also calculate the branching fractions of the
processes, $\tau\to \mu\pi$, $\tau\to \mu\eta^{(\prime)}$ and $\tau\to\mu a_1$,
which are dominated by the $Z$-boson exchanges due to the spin and the parity
of the hadrons.; Comment: 24 pages, 10 figures
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Search for a pseudoscalar boson decaying into a Z boson and the 125 GeV Higgs boson in llbb final states
Fonte: Universidade Cornell
Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
46.32%
Results are reported on a search for decays of a pseudoscalar A boson into a
Z boson and a light scalar h boson, where the Z boson decays into a pair of
oppositely-charged electrons or muons, and the h boson decays into b anti-b.
The search is based on data from proton-proton collisions at a center-of-mass
energy sqrt(s)=8 TeV collected with the CMS detector, corresponding to an
integrated luminosity of 19.7 inverse femtobarns. The h boson is assumed to be
the standard model-like Higgs boson with a mass of 125 GeV. With no evidence
for signal, upper limits are obtained on the product of the production cross
section and the branching fraction of the A boson in the Zh channel. Results
are also interpreted in the context of two Higgs doublet models.; Comment: Replaced with published version. Added journal reference
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Invisible Z-Boson Decays at e+e- Colliders
Fonte: Universidade Cornell
Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 05/08/2003
Relevância na Pesquisa
46.37%
The measurement of the invisible Z-boson decay width at e+e- colliders can be
done "indirectly", by subtracting the Z-boson visible partial widths from the
Z-boson total width, or "directly", from the process e+e- -> \gamma \nu
\bar{\nu}. Both procedures are sensitive to different types of new physics and
provide information about the couplings of the neutrinos to the Z-boson. At
present, measurements at LEP and CHARM II are capable of constraining the
left-handed Z\nu\nu-coupling, 0.45 <~ g_L <~ 0.5, while the right-handed one is
only mildly bounded, |g_R| <= 0.2. We show that measurements at a future e+e-
linear collider at different center-of-mass energies, \sqrt{s} = MZ and
\sqrt{s}s ~ 170 GeV, would translate into a markedly more precise measurement
of the Z\nu\nu-couplings. A statistically significant deviation from Standard
Model predictions will point toward different new physics mechanisms, depending
on whether the discrepancy appears in the direct or the indirect measurement of
the invisible Z-width. We discuss some scenarios which illustrate the ability
of different invisible Z-boson decay measurements to constrain new physics
beyond the Standard Model.
Link permanente para citações:
Z-Boson Decays in a Strong Electromagnetic Field
Fonte: Universidade Cornell
Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 11/09/2013
Relevância na Pesquisa
46.37%
The probability of Z-boson decay to a pair of charged fermions in a strong
electromagnetic field, is calculated. On the basis of a method that employs
exact solutions to relativistic wave equations for charged particles, analytic
expressions for the partial decay widths of Z-boson are obtained at an
arbitrary value the external-field strength. The total Z-boson decay width in
an intense electromagnetic field, is calculated by summing these results over
all known generations of charged leptons and quarks. It is found that, in the
region of relatively weak fields, the field-induced corrections to the standard
Z-boson decay width in a vacuum do not exceed 2%. As the external-field
strength increases, the total decay width develops oscillations against the
background of its gradual decrease to the absolute-minimum point. In the region
of strong fields the total decay width of Z-boson grows monotonically. In this
case the t-quark-production process, which is forbidden in the absence of an
external field, begins contributing significantly to the total decay width of
the Z-boson.; Comment: 40 pages, 11 Postscript figures
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Pair production of Higgs bosons associated with $Z$ boson in the left-right twin Higgs model at the ILC
Fonte: Universidade Cornell
Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
46.36%
The left-right twin Higgs(LRTH) model predicts the existence of three
additional Higgs bosons: one neutral Higgs $\phi^{0}$ and a pair of charged
Higgs bosons $\phi^{\pm}$. In this paper, we studied the production of a pair
of charged and neutral Higgs bosons associated with standard model gauge boson
$Z$ at the ILC, i.e., $e^{+}e^{-}\rightarrow Z\phi^{+}\phi^{-}$ and
$e^{+}e^{-}\rightarrow Z\phi^{0}\phi^{0}$. We calculate the production rate and
present the distributions of the various observables, such as, the
distributions of the energy and the transverse momenta of final $Z$-boson and
charged Higgs boson $\phi^{-}$, the differential cross section of the invariant
mass of charged Higgs bosons pair, the distribution of the angle between
charged Higgs bosons pair and the production angle distributions of $Z$-boson
and charged Higgs boson $\phi^{-}$. Our numerical results show that, for the
process $e^{+}e^{-}\rightarrow Z\phi^{+}\phi^{-}$, the production rates are at
the level of $10^{-1} fb$ with reasonable parameter values. For the process of
$e^{+}e^{-}\rightarrow Z\phi^{0}\phi^{0}$, we find that the production cross
section are smaller than $6\times 10^{-3} fb$ in most of parameter space.
However, the resonance production cross section can be significantly enhanced.; Comment: 20 pages...
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Observation of associated production of a $Z$ boson with a $D$ meson in the~forward region
Fonte: Universidade Cornell
Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 14/01/2014
Relevância na Pesquisa
56.29%
A search for associated production of a $Z$ boson with an open charm meson is
presented using a data sample, corresponding to an integrated luminosity of
$1.0\,\mathrm{fb}^{-`}$ of proton--proton collisions at a centre-of-mass energy
of 7\,TeV, collected by the LHCb experiment. %% Seven candidate events for
associated production of a $Z$ boson with a $D^0$ meson and four candidate
events for a $Z$ boson with a $D^+$ meson are observed with a combined
significance of 5.1standard deviations. The production cross-sections in the
forward region are measured to be $$\sigma_{Z\rightarrow\mu^+\mu^-\!,D^0} =
2.50\pm1.12\pm0.22pb$$ $$\sigma_{Z\rightarrow\mu^+\mu^-\!,D^+} =
0.44\pm0.23\pm0.03pb,$$ where the first uncertainty is statistical and the
second systematic.; Comment: 18 pages, 2 figures
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Search for the SM Higgs boson in the (W/Z)H channel with H → bb using the ATLAS detector at the LHC
Fonte: [Barcelona] : Universitat Autònoma de Barcelona,
Publicador: [Barcelona] : Universitat Autònoma de Barcelona,
Tipo: Tesis i dissertacions electròniques; info:eu-repo/semantics/doctoralThesis; info:eu-repo/semantics/publishedVersion
Formato: application/pdf
Publicado em //2015
ENG
Relevância na Pesquisa
46.48%
Esta tesis presenta los últimos resultados de ATLAS en la búsqueda del bosón de Higgs del Modelo Estándar (SM) en su decaimiento a un par de quarks-b. La búsqueda del bosón de Higgs se realiza en los canales de producción asociados con un bosón vectorial W o Z en el estado final. Ésta incluye el decaimiento leptónico (electrón y muón) del bosón vectorial además del canal en el que el bosón Z decae a un par de neutrinos. En particular, este documento se centra en el canal ZH (Z → νν and H → bb). El análisis utiliza todos los datos generados por colisiones de protones en el experimento ATLAS a √s = 7TeV y √s = 8 TeV. El análisis se basa en una compleja caracterización de eventos en función del modo de decaimiento del bosón vectorial, el número de jets y de b-jets en el estado final, y el momento transverso del bosón vectorial. Esto permite hacer un estudio detallado de los principales procesos de fondo. Dos enfoques diferentes se consideran para el análisis: la utilización de la distribución de mbb como variable principal de discriminación o el uso de una técnica multivariante de redes neuronales. El análisis utiliza una compleja estrategia de ajuste de datos y predicciones de fondo en regiones de control y señal que posibilita constreñir los procesos de fondo...
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Estimation of the Z->vv background to New Physics searches in ATLAS
Fonte: University of Cambridge; Department of Physics; Wolfson College; CERN; Cavendish Laboratory
Publicador: University of Cambridge; Department of Physics; Wolfson College; CERN; Cavendish Laboratory
Tipo: Thesis; doctoral; PhD
EN
Relevância na Pesquisa
56.09%
This thesis describes a series of studies related to searches for new phenomena, beyond the Standard Model of particle physics, in high energy hadron collisions. In such searches, it becomes crucial to identify the Standard Model backgrounds in order to resolve a potential new signal. The thesis presents a method that uses photon events to determine one of such backgrounds, caused by the production of Z boson events. The studies performed to validate the method, both theoretically and experimentally, are presented and the method was shown to be successful as well as to provide reliable results. Theoretically, the method is found to be robust up to a ~10% uncertainty. Experimentally, the method is implemented to estimate the Z(vv) + jets background for the SUSY 0l + E_T^miss + jets search in the ATLAS experiment at the Large Hadron Collider, where this background is one of the most important components for the final sensitivity and is impossible to measure directly. The main experimental results presented are the latest from ATLAS at the time of writing, corresponding to the full dataset of proton-proton collisions delivered by the LHC in 2011 (4.7 fb^-1) at a centre of mass energy of 7 TeV. Given that this method has been mainstream since 2010...
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Measurement of the cross-section for b-jets produced in association with a Z boson at √s = 7 TeV with the ATLAS detector
Fonte: Elsevier
Publicador: Elsevier
Tipo: Article; PeerReviewed
Formato: application/pdf
Publicado em 05/01/2012
Relevância na Pesquisa
56.22%
A measurement is presented of the inclusive cross-section for b-jet production in association with a Z boson in pp collisions at a centre-of-mass energy of √s = 7TeV. The analysis uses the data sample collected by the ATLAS experiment in 2010, corresponding to an integrated luminosity of approximately 36 pb^(−1). The event selection requires a Z boson decaying into high p_T electrons or muons, and at least one b-jet, identified by its displaced vertex, with transverse momentum p_T>25 GeV and rapidity |y|<2.1. After subtraction of background processes, the yield is extracted from the vertex mass distribution of the candidate b-jets. The ratio of this cross-section to the inclusive Z cross-section (the average number of b-jets per Z event) is also measured. Both results are found to be in good agreement with perturbative QCD predictions at next-to-leading order.
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Search for Pair Production of a New b' Quark that Decays into a Z Boson and a Bottom Quark with the ATLAS Detector
Fonte: American Physical Society
Publicador: American Physical Society
Tipo: Article; PeerReviewed
Formato: application/pdf
Publicado em 17/08/2012
Relevância na Pesquisa
56.2%
A search is reported for the pair production of a new quark b′ with at least one b′ decaying to a Z boson and a bottom quark. The data, corresponding to 2.0 fb^(-1) of integrated luminosity, were collected from pp collisions at √s=7 TeV with the ATLAS detector at the CERN Large Hadron Collider. Using events with a b-tagged jet and a Z boson reconstructed from opposite-charge electrons, the mass distribution of large transverse momentum b′ candidates is tested for an enhancement. No evidence for a b′ signal is detected in the observed mass distribution, resulting in the exclusion at a 95% confidence level of b′ quarks with masses m_b′<400 GeV that decay entirely via b′→Z+b. In the case of a vectorlike singlet b′ mixing solely with the third standard model generation, masses m_b′<358 GeV are excluded.
Link permanente para citações:
Search for a pseudoscalar boson decaying into a Z boson and the 125 GeV Higgs boson in ℓ+ℓ−bb final states
Fonte: Elsevier
Publicador: Elsevier
Tipo: Article; PeerReviewed
Formato: application/pdf; application/pdf
Publicado em 02/09/2015
Relevância na Pesquisa
46.32%
Results are reported on a search for decays of a pseudoscalar A boson into a Z boson and a light scalar h boson, where the Z boson decays into a pair of oppositely-charged electrons or muons, and the h boson decays into bb‾. The search is based on data from proton–proton collisions at a center-of-mass energy √s=8 TeV collected with the CMS detector, corresponding to an integrated luminosity of 19.7 fb^(−1). The h boson is assumed to be the standard model-like Higgs boson with a mass of 125 GeV. With no evidence for signal, upper limits are obtained on the product of the production cross section and the branching fraction of the A boson in the Zh channel. Results are also interpreted in the context of two Higgs doublet models.
Link permanente para citações: