2,841 research outputs found
Photon-hadron and photon-photon collisions in CMS (including data from p-p, p-A and A-A collisions)
No full textPhoton-nucleus and photon-photon collisions are abundantly produced at the LHC. The LHC provides a unique opportunity to study high-energy photon-photon interactions, thanks to its high energy and large integrated luminosity. In this talk two CMS analyses concerning photon-hadron and photon-photon collisions are going to be presented. The first deals with the measurement of the coherent photoproduction cross section in ultra-peripheral PbPb collisions at = 2.76 TeV in conjunction with forward neutrons. The second one shows the evidence of the exclusive production and improvement on constraints for the anomalous gauge quartic coupling parameters
Two-photon fusion Higgs production in collisions with proton and ion beams at the LHC, HE-LHC, and FCC
No full textThe production of the Higgs boson in ultraperipheral collisions (UPCs) of proton and nuclear beams at three future colliders — the high-luminosity Large Hadron Collider (HL-LHC), the high-energy LHC (HE-LHC), and the Future Circular Collider (FCC) — is studied. The cross sections for the process AA (A)H(A), with the Higgs particle produced via two-photon fusion at midrapidity and the hadron(s) A surviving the interaction, are computed with MADGRAPH 5 extended with the corresponding coherent fluxes for Pb-Pb, Xe-Xe, Kr-Kr, Ar-Ar, O-O, p-Pb, and p-p collisions over ≈ 3–100 TeV. Taking into account the expected luminosities for all colliding systems, the yields and significances for observing the Higgs boson in UPCs, on top of the → b,c,q continuum backgrounds, at the three future colliders are estimated.At HL-LHC and HE-LHC, the systems with larger Higgs significance are Ar-Ar(6.3TeV) and Kr-Kr(12.5 TeV) respectively. However, evidence for → H production would require ×200 and ×30 times larger integrated luminosities at both machines. Factors of ten can be gained by running for a year, rather than the typical 1-month heavy-ion run at the LHC, but the process will likely remain unobserved unless a higher energy collider such as the FCC is built. In the latter machine, a 5 observation of → H is warranted in just the first nominal Pb-Pb and p-Pb runs
Searches for axion-like particles via fusion at future colliders
No full textOpportunities for searches for axionlike particles (ALPs) coupling to photons in e+e- collisions at the Future Circular Collider (FCC-ee) and International Linear Collider (ILC) are investigated. We perform a study of the photon-fusion production of ALPs decaying into two photons, e+e-→γγe+a(γγ)e-, over the light-by-light continuum background, for the planned FCC-ee and ILC center-of-mass energies and integrated luminosities. An analysis of the feasibility measurements is presented using parametrized simulations for two types of detectors. Upper limits at 95% confidence level (C.L.) on the cross section for ALP production, σ(γγ→a→γγ), and on the ALP-photon coupling are obtained over the ma≈0.1–1000 GeV ALP mass range, and compared to current and future collider searches. Production cross sections down to σ(γγ→a→γγ)≈1 fb (1 ab) will be probed at ma≈1 (300) GeV, corresponding to constraints on the axion-photon coupling as low as gaγγ≈2×10-3 TeV-1.Opportunities for searches for axion-like particles (ALPs) coupling to photons in collisions at the Future Circular Collider (FCC-ee) and International Linear Collider (ILC) are investigated. We perform a study of the photon-fusion production of ALPs decaying into two photons, , over the light-by-light continuum background, for the planned FCC-ee and ILC center-of-mass energies and integrated luminosities. An analysis of the feasibility measurements is presented using parametrized simulations for two types of detectors. Upper limits at 95% confidence level (CL) on the cross section for ALP production, , and on the ALP-photon coupling are obtained over the --1000 GeV ALP mass range, and compared to current and future collider searches. Production cross sections down to fb (1 ab) will be probed at (300) GeV, corresponding to constraints on the axion-photon coupling as low as TeV
Higgs boson production in photon-photon interactions with proton, light-ion, and heavy-ion beams at current and future colliders
No full textThe production of the Higgs boson in photon-photon interactions with proton and nucleus beams at three planned or proposed future CERN colliders --- the high-luminosity Large Hadron Collider (HL-LHC), the high-energy LHC (HE-LHC), and the Future Circular Collider (FCC) --- is studied. The cross sections for the process AA(A)H(A), with the ions A surviving the interaction and the Higgs scalar exclusively produced, are computed with MadGraph 5 modified to include the corresponding elastic fluxes, for Pb-Pb, Xe-Xe, Kr-Kr, Ar-Ar, O-O, p-Pb, and p-p over the nucleon-nucleon collision energy range --100 TeV. Simulations of the decay mode --- including realistic (mis)tagging and reconstruction efficiencies for the final-state b-jets, as well as appropriate kinematical selection criteria to reduce the similarly computed continuum backgrounds --- have been carried out. Taking into account the expected luminosities for all systems, the yields and significances for observing the Higgs boson in ultraperipheral collisions (UPCs) are estimated. At the HL-LHC and HE-LHC, the colliding systems with larger Higgs significance are Ar-Ar(6.3 TeV) and Kr-Kr(12.5 TeV) respectively, but evidence for two-photon Higgs production would require 200 and 30 times larger integrated luminosities than those planned today at both machines. Factors of ten can be gained by running for a year, rather than the typical 1-month heavy-ion LHC operation, but the process will likely remain unobserved until a higher energy hadron collider, such as the FCC, is built. In the latter machine, the observation of Higgs production in UPCs is feasible in just the first nominal run of Pb-Pb and p-Pb collisions at and 63 TeV respectively.The production of the Higgs boson in photon-photon interactions with proton and nucleus beams at three planned or proposed future CERN colliders --- the high-luminosity Large Hadron Collider (HL-LHC), the high-energy LHC (HE-LHC), and the Future Circular Collider (FCC) --- is studied. The cross sections for the process AA(A)H(A), with the ions A surviving the interaction and the Higgs scalar exclusively produced, are computed with MadGraph 5 modified to include the corresponding elastic fluxes, for Pb-Pb, Xe-Xe, Kr-Kr, Ar-Ar, O-O, p-Pb, and p-p over the nucleon-nucleon collision energy range --100 TeV. Simulations of the decay mode --- including realistic (mis)tagging and reconstruction efficiencies for the final-state b-jets, as well as appropriate kinematical selection criteria to reduce the similarly computed continuum backgrounds --- have been carried out. Taking into account the expected luminosities for all systems, the yields and significances for observing the Higgs boson in ultraperipheral collisions (UPCs) are estimated. At the HL-LHC and HE-LHC, the colliding systems with larger Higgs significance are Ar-Ar(6.3 TeV) and Kr-Kr(12.5 TeV) respectively, but evidence for two-photon Higgs production would require 200 and 30 times larger integrated luminosities than those planned today at both machines. Factors of ten can be gained by running for a year, rather than the typical 1-month heavy-ion LHC operation, but the process will likely remain unobserved until a higher energy hadron collider, such as the FCC, is built. In the latter machine, the observation of Higgs production in UPCs is feasible in just the first nominal run of Pb-Pb and p-Pb collisions at and 63 TeV respectively
Os direitos do homem e o neoliberalismo
No full textDissertação (mestrado) - Universidade Federal de Santa Catarina, Centro de Ciencias JuridicasA pesquisa, cujo resultados ora se apresenta, teve por propósito investigar o impacto do neoliberalismo, seja como proposta teórica (Hayek) seja como prática política (governos Tatcher-Major e Reagan-Bush), sobre os direitos do homem, notadamente sobre os direitos denominados de econômicos e sociais. A realização de tal objetivo deu-se basicamente através de uma pesquisa bibliográfica de cunho multidisciplinar, de uma leitura da legislação constitucional brasileira e estrangeira e de uma análise dos vários instrumentos nacionais e internacionais de proteção dos direitos do homem. A dissertação desdobra-se em três grandes capítulos. O primeiro capítulo analisa as condições políticas que possibilitaram o surgimento dos direitos do homem no decorrer dos séculos XVII e XVIII. O segundo capítulo verifica o desenvolvimento histórico dos direitos do homem a partir da Declaração de Direitos da Virgínia (1776) e da Declaração dos Direitos do Homem e do Cidadão (1789). O terceiro capítulo demostra o momento do surgimento do neoliberalismo, verifica a sua base teórica, analisa a sua chegada ao poder e, por último, investiga o seu impacto sobre os direiros do homem, principalmente sobre os direitos econômicos e sociais. Sem estabelecer conclusões definitivas e absolutas, as considerações finais acentuam as conseqüências negativas em relação à luta pelos direitos do homem advindas com o surgimento do neoliberalismo e realçam a importância do reconhecimento e do respeito dos direitos do homem como forma de garantir uma vida melhor e uma convivência democrática e solidária entre os homens
Anomalous photon-gauge boson coupling contribution to the exclusive vector boson pair production from two photon exchange in pp collisions at 13 TeV
No full textAuthor Correction: A portrait of the Higgs boson by the CMS experiment ten years after the discovery
No full textIn the version of this article initially published, CMS Collaboration author names, affiliations and acknowledgements were omitted and have now been included in the HTML and PDF versions of the articl
Recommended from our members
Author Correction: A portrait of the Higgs boson by the CMS experiment ten years after the discovery
No full textCorrection to: Nature Published online 4 July 2022 In the version of this article initially published, CMS Collaboration author names, affiliations and acknowledgements were omitted and have now been included in the HTML and PDF versions of the article
Observation of Λ Hyperon Local Polarization in p-Pb Collisions at √sNN=8.16 TeV
No full textThe polarization of the Λ and ̄Λ hyperons along the beam direction has been measured in proton-lead (p-Pb) collisions at a center-of-mass energy per nucleon pair of 8.16 TeV. The data were obtained with the CMS detector at the LHC and correspond to an integrated luminosity of 186.0±6.5 nb−1
. A significant azimuthal dependence of the hyperon polarization, characterized by the second-order Fourier sine coefficient Pz,s2, is observed. The Pz,s2 values decrease as a function of charged particle multiplicity, but increase with transverse momentum. A hydrodynamic model that describes the observed Pz,s2 values in nucleus-nucleus collisions by introducing vorticity effects does not reproduce either the sign or the magnitude of the p-Pb results. These observations pose a challenge to the current theoretical implementation of spin polarization in heavy ion collisions and offer new insights into the origin of spin polarization in hadronic collisions at LHC energies
- …
