scholarly journals BLACK HOLES AND ASYMPTOTICALLY SAFE GRAVITY

2012 ◽  
Vol 27 (05) ◽  
pp. 1250019 ◽  
Author(s):  
KEVIN FALLS ◽  
DANIEL F. LITIM ◽  
AARTI RAGHURAMAN
Keyword(s):  
Black Holes ◽  
Quantum Gravity ◽  
Cross Sections ◽  
Production Cross ◽  
Hadron Collider ◽  
Conformal Structure ◽  
Gravity Models ◽  
Particle Collisions ◽  
Penrose Diagram ◽  
Black Hole Remnant

Quantum gravitational corrections to black holes are studied in four and higher dimensions using a renormalisation group improvement of the metric. The quantum effects are worked out in detail for asymptotically safe gravity, where the short-distance physics is characterized by a nontrivial fixed point of the gravitational coupling. We find that a weakening of gravity implies a decrease of the event horizon, and the existence of a Planck-size black hole remnant with vanishing temperature and vanishing heat capacity. The absence of curvature singularities is generic and discussed together with the conformal structure and the Penrose diagram of asymptotically safe black holes. The production cross-section of mini-black holes in energetic particle collisions, such as those at the Large Hadron Collider, is analysed within low-scale quantum gravity models. Quantum gravity corrections imply that cross-sections display a threshold, are suppressed in the Planckian, and reproduce the semiclassical result in the deep trans-Planckian region. Further implications are discussed.

scholarly journals Heavy-flavor hadro-production with heavy-quark masses renormalized in the $$ \overline{\mathrm{MS}} $$, MSR and on-shell schemes

2021 ◽  
Vol 2021 (4) ◽  
Author(s):  
M. V. Garzelli ◽  
L. Kemmler ◽  
S. Moch ◽  
O. Zenaiev
Keyword(s):  
Heavy Quark ◽  
Cross Sections ◽  
Top Quark ◽  
Quark Mass ◽  
Production Cross ◽  
Hadron Collider ◽  
Distribution Functions ◽  
Heavy Flavor ◽  
Parton Distribution Functions ◽  
Heavy Quark Mass

Abstract We present predictions for heavy-quark production at the Large Hadron Collider making use of the $$ \overline{\mathrm{MS}} $$ MS ¯ and MSR renormalization schemes for the heavy-quark mass as alternatives to the widely used on-shell renormalization scheme. We compute single and double differential distributions including QCD corrections at next-to-leading order and investigate the renormalization and factorization scale dependence as well as the perturbative convergence in these mass renormalization schemes. The implementation is based on publicly available programs, MCFM and xFitter, extending their capabilities. Our results are applied to extract the top-quark mass using measurements of the total and differential $$ t\overline{t} $$ t t ¯ production cross-sections and to investigate constraints on parton distribution functions, especially on the gluon distribution at low x values, from available LHC data on heavy-flavor hadro-production.

scholarly journals Charged current Drell-Yan production at N3LO

2020 ◽  
Vol 2020 (11) ◽  
Author(s):  
Claude Duhr ◽  
Falko Dulat ◽  
Bernhard Mistlberger
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Production Cross Section ◽  
Production Cross ◽  
Hadron Collider ◽  
Charge Asymmetry ◽  
Charged Current ◽  
Leading Order ◽  
Neutrino Pair ◽  
The Impact

Abstract We present the production cross section for a lepton-neutrino pair at the Large Hadron Collider computed at next-to-next-to-next-to-leading order (N3LO) in QCD perturbation theory. We compute the partonic coefficient functions of a virtual W± boson at this order. We then use these analytic functions to study the progression of the perturbative series in different observables. In particular, we investigate the impact of the newly obtained corrections on the inclusive production cross section of W± bosons, as well as on the ratios of the production cross sections for W+, W− and/or a virtual photon. Finally, we present N3LO predictions for the charge asymmetry at the LHC.

scholarly journals A REVIEW OF QUANTUM GRAVITY AT THE LARGE HADRON COLLIDER

2010 ◽  
Vol 25 (19) ◽  
pp. 1553-1579 ◽  
Author(s):  
XAVIER CALMET
Keyword(s):  
Black Holes ◽  
Large Hadron Collider ◽  
Quantum Gravity ◽  
Hadron Collider ◽  
Planck Mass ◽  
Small Quantum ◽  
Recent Developments ◽  
Dimensional Models

The aim of this paper is to review the recent developments in the phenomenology of quantum gravity at the Large Hadron Collider. We shall pay special attention to four-dimensional models which are able to lower the reduced Planck mass to the TeV region and compare them to models with a large extra-dimensional volume. We then turn our attention to reviewing the emission of gravitons (massless or massive) at the LHC and to the production of small quantum black holes.

scholarly journals NONCOMMUTATIVE BLACK HOLES, THE FINAL APPEAL TO QUANTUM GRAVITY: A REVIEW

2009 ◽  
Vol 24 (07) ◽  
pp. 1229-1308 ◽  
Author(s):  
PIERO NICOLINI
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Quantum Gravity ◽  
Effective Theory ◽  
Final State ◽  
Curved Space ◽  
Higher Dimensional ◽  
Energy Hadron ◽  
Black Hole Remnant ◽  
First Time

We present the state of the art regarding the relation between the physics of Quantum Black Holes and Noncommutative Geometry. We start with a review of models proposed in the literature for describing deformations of General Relativity in the presence of noncommutativity, seen as an effective theory of Quantum Gravity. We study the resulting metrics, proposed to replace or at least to improve the conventional black hole solutions of Einstein's equation. In particular, we analyze noncommutative-inspired solutions obtained in terms of quasiclassical noncommutative coordinates: indeed because of their surprising new features, these solutions enable us to circumvent long standing problems with Quantum Field Theory in Curved Space and to cure the singular behavior of gravity at the centers of black holes. As a consequence, for the first time, we get a complete description of what we may call the black hole SCRAM, the shut down of the emission of thermal radiation from the black hole: in place of the conventional scenario of runaway evaporation in the Planck phase, we find a zero temperature final state, a stable black hole remnant, whose size and mass are determined uniquely in terms of the noncommutative parameter θ. This result turns out to be of vital importance for the physics of the forthcoming experiments at the LHC, where mini black hole production is foreseen in extreme energy hadron collisions. Because of this, we devote the final part of this review to higher-dimensional solutions and their phenomenological implications for TeV Gravity.

GUP-corrected thermodynamics of accelerating and rotating black holes

2017 ◽  
Vol 26 (05) ◽  
pp. 1741018 ◽  
Author(s):  
Muhammad Rizwan ◽  
K. Saifullah
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Quantum Gravity ◽  
Black Hole Physics ◽  
Generalized Uncertainty Principle ◽  
Hawking Temperature ◽  
Rotating Black Holes ◽  
Gravity Effects ◽  
Klein Gordon ◽  
Black Hole Remnant

When quantum gravity effects, that are based on generalized uncertainty principle with a minimal measurable length, are incorporated into black hole physics the Klein–Gordon and Dirac equations get modified. Using these modified equations we investigate tunneling of scalar particles and fermions from event and acceleration horizons of accelerating and rotating black holes and obtain the modified Hawking temperature with quantum gravity effects. We see that Hawking temperature depends on black hole parameters as well as the quantum numbers of emitted fermions. The quantum corrections slow down black hole evaporation and leave a black hole remnant. This contradicts complete evaporation of a black hole which is presaged by the standard temperature formula for black holes. The modified Hawking temperatures presented here, in appropriate limits, are consistent with the previous results in the literature.

scholarly journals Measurement of fiducial and differential $$W^+W^-$$ production cross-sections at $$\sqrt{s}=13$$ TeV with the ATLAS detector

2019 ◽  
Vol 79 (10) ◽  
Author(s):  
M. Aaboud ◽  
◽  
G. Aad ◽  
B. Abbott ◽  
D. C. Abbott ◽  
...  
Keyword(s):  
Transverse Momentum ◽  
Cross Section ◽  
Cross Sections ◽  
Top Quark ◽  
Production Cross ◽  
Hadron Collider ◽  
Effective Field ◽  
Electroweak Gauge Boson ◽  
Using Data ◽  
Background Events

Abstract A measurement of fiducial and differential cross-sections for $$W^+W^-$$W+W- production in proton–proton collisions at $$\sqrt{s}=13$$s=13 TeV with the ATLAS experiment at the Large Hadron Collider using data corresponding to an integrated luminosity of 36.1 $$\hbox {fb}^{-1}$$fb-1 is presented. Events with one electron and one muon are selected, corresponding to the decay of the diboson system as $$WW\rightarrow e^{\pm }\nu \mu ^{\mp }\nu $$WW→e±νμ∓ν. To suppress top-quark background, events containing jets with a transverse momentum exceeding 35 GeV are not included in the measurement phase space. The fiducial cross-section, six differential distributions and the cross-section as a function of the jet-veto transverse momentum threshold are measured and compared with several theoretical predictions. Constraints on anomalous electroweak gauge boson self-interactions are also presented in the framework of a dimension-six effective field theory.

scholarly journals Search for excited electrons singly produced in proton–proton collisions at $$\sqrt{s} ~=~13~\text {Te}\text {V}$$ with the ATLAS experiment at the LHC

2019 ◽  
Vol 79 (9) ◽  
Author(s):  
M. Aaboud ◽  
◽  
G. Aad ◽  
B. Abbott ◽  
D. C. Abbott ◽  
...  
Keyword(s):  
Cross Sections ◽  
Production Cross ◽  
Hadron Collider ◽  
Excited Electron ◽  
Electron Mass ◽  
Large Radius ◽  
Final States ◽  
Hadronic Jets ◽  
Proton Proton ◽  
Atlas Experiment

Abstract A search for excited electrons produced in pp collisions at $$\sqrt{s}$$s  = 13 $$\text {Te}\text {V}$$Te via a contact interaction $$q{\bar{q}}\rightarrow ee^*$$qq¯→ee∗ is presented. The search uses 36.1 fb$$^{-1}$$-1 of data collected in 2015 and 2016 by the ATLAS experiment at the Large Hadron Collider. Decays of the excited electron into an electron and a pair of quarks ($$eq{\bar{q}}$$eqq¯) are targeted in final states with two electrons and two hadronic jets, and decays via a gauge interaction into a neutrino and a $$W$$W boson ($$\nu W$$νW) are probed in final states with an electron, missing transverse momentum, and a large-radius jet consistent with a hadronically decaying $$W$$W boson. No significant excess is observed over the expected backgrounds. Upper limits are calculated for the $$pp \rightarrow ee^*\rightarrow eeq{\bar{q}} $$pp→ee∗→eeqq¯ and $$pp \rightarrow ee^*\rightarrow e\nu W $$pp→ee∗→eνW production cross sections as a function of the excited electron mass $$m_{e^*}$$me∗ at 95% confidence level. The limits are translated into lower bounds on the compositeness scale parameter $$\Lambda $$Λ of the model as a function of $$m_{e^*}$$me∗. For $$m_{e^*} <0.5$$me∗<0.5 $$\text {Te}\text {V}$$Te, the lower bound for $$\Lambda $$Λ is 11 $$\text {Te}\text {V}$$Te. In the special case of $$m_{e^*} =\Lambda $$me∗=Λ, the values of $$m_{e^*} <4.8$$me∗<4.8 $$\text {Te}\text {V}$$Te are excluded. The presented limits on $$\Lambda $$Λ are more stringent than those obtained in previous searches.

scholarly journals DeepXS: fast approximation of MSSM electroweak cross sections at NLO

2020 ◽  
Vol 80 (1) ◽  
Author(s):  
Sydney Otten ◽  
Krzysztof Rolbiecki ◽  
Sascha Caron ◽  
Jong-Soo Kim ◽  
Roberto Ruiz de Austri ◽  
...  
Keyword(s):  
Cross Sections ◽  
Particle Production ◽  
Production Cross ◽  
Hadron Collider ◽  
Distribution Functions ◽  
Monte Carlo Integration ◽  
Leading Order ◽  
Parton Distribution Functions ◽  
Dimensional Parameter ◽  
O 10

AbstractWe present a deep learning solution to the prediction of particle production cross sections over a complicated, high-dimensional parameter space. We demonstrate the applicability by providing state-of-the-art predictions for the production of charginos and neutralinos at the Large Hadron Collider (LHC) at the next-to-leading order in the phenomenological MSSM-19 and explicitly demonstrate the performance for $$pp\rightarrow \tilde{\chi }^+_1\tilde{\chi }^-_1,$$pp→χ~1+χ~1-,$$\tilde{\chi }^0_2\tilde{\chi }^0_2$$χ~20χ~20 and $$\tilde{\chi }^0_2\tilde{\chi }^\pm _1$$χ~20χ~1± as a proof of concept which will be extended to all SUSY electroweak pairs. We obtain errors that are lower than the uncertainty from scale and parton distribution functions with mean absolute percentage errors of well below $$0.5\,\%$$0.5% allowing a safe inference at the next-to-leading order with inference times that improve the Monte Carlo integration procedures that have been available so far by a factor of $$\mathscr {O}(10^7)$$O(107) from $$\mathscr {O}(\mathrm{min})$$O(min) to $$\mathscr {O}(\mu \mathrm{s})$$O(μs) per evaluation.

scholarly journals Top quark anomalous couplings at the high-luminosity phase of the LHC

2019 ◽  
Vol 34 (18) ◽  
pp. 1950142 ◽  
Author(s):  
Frédéric Déliot ◽  
Miguel C. N. Fiolhais ◽  
António Onofre
Keyword(s):  
Cross Sections ◽  
Top Quark ◽  
W Boson ◽  
Production Cross ◽  
Hadron Collider ◽  
Center Of Mass ◽  
High Luminosity ◽  
Anomalous Couplings ◽  
Center Of Mass Energy ◽  
Single Top

The combination of the latest and most precise measurements of several top quark properties is presented in this paper in order to establish allowed regions on anomalous contributions to the Lorentz structure of the Wtb vertex. These measurements include single top production cross-sections, W boson helicity fractions and forward–backward asymmetries, both at Tevatron and at the Large Hadron Collider (LHC), up to a center-of-mass energy of 13 TeV. The results obtained at 95% Confidence Level (CL) for the top quark anomalous couplings are compared with the limits extracted from a combination that includes the expected measurements at the future High-Luminosity run of the LHC.

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