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L. Reina

Publications and source records attributed to L. Reina.

At least 37 records · Page 2Linked to original sources
arXiv2013

Report of the Snowmass 2013 energy frontier QCD working group

This is the summary report of the energy frontier QCD working group prepared for Snowmass 2013. We review the status of tools, both theoretical and experimental, for understanding the strong interactions at colliders. We attempt to prioritize important directions that future developments should take. Most of the efforts of the QCD working group concentrate on proton-proton colliders, at 14 TeV as planned for the next run of the LHC, and for 33 and 100 TeV, possible energies of the colliders that will be necessary to carry on the physics program started at 14 TeV. We also examine QCD predictions and measurements at lepton-lepton and lepton-hadron colliders, and in particular their ability to improve our knowledge of strong coupling constant and parton distribution functions.

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arXiv2012

Handbook of LHC Higgs Cross Sections: 2. Differential Distributions

This Report summarises the results of the second year's activities of the LHC Higgs Cross Section Working Group. The main goal of the working group was to present the state of the art of Higgs Physics at the LHC, integrating all new results that have appeared in the last few years. The first working group report Handbook of LHC Higgs Cross Sections: 1. Inclusive Observables (CERN-2011-002) focuses on predictions (central values and errors) for total Higgs production cross sections and Higgs branching ratios in the Standard Model and its minimal supersymmetric extension, covering also related issues such as Monte Carlo generators, parton distribution functions, and pseudo-observables. This second Report represents the next natural step towards realistic predictions upon providing results on cross sections with benchmark cuts, differential distributions, details of specific decay channels, and further recent developments.

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arXiv2011

NLO QCD predictions for W+1 jet and W+2 jet production with at least one b jet at the 7 TeV LHC

We calculate the production of a W boson in association with up to two jets including at least one b-jet to next-to-leading order (NLO) in QCD at the CERN Large Hadron Collider with 7 TeV center-of-mass energy. Both exclusive and inclusive event cross section and b-jet cross sections are presented. The calculation is performed consistently in the five-flavor-number scheme where both q anti-q' and bq (q =\= b) initiated parton level processes are included at NLO QCD. We study the residual theoretical uncertainties of the NLO predictions due to the renormalization and factorization scale dependence, to the uncertainty from the parton distribution functions, and to the values of alpha_s and the bottom-quark mass.

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arXiv2011

Handbook of LHC Higgs Cross Sections: 1. Inclusive Observables

This Report summarizes the results of the first 10 months' activities of the LHC Higgs Cross Sections Working Group. The main goal of the working group was to present the status-of-art on Higgs Physics at the LHC integrating all new results that have appeared in the last few years. The Report is more than a mere collection of the proceedings of the general meetings. The subgroups have been working in different directions. An attempt has been made to present the first Report from these subgroups in a complete and homogeneous form. The subgroups' contributions correspondingly comprise the main parts of the Report. A significant amount of work has been performed in providing higher-order corrections to the Higgs-boson cross sections and pinning down the theoretical uncertainty of the Standard Model predictions. This Report comprises explicit numerical results on total cross sections, leaving the issues of event selection cuts and differential distributions to future publications. The subjects for further study are identified.

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arXiv2009

W- and Z-boson production with a massive bottom-quark pair at the Large Hadron Collider

We present total and differential cross sections for W b anti-b and Z b anti-b production at the CERN Large Hadron Collider with a center-of-mass energy of 14 TeV, including Next-to-Leading Order (NLO) QCD corrections and full bottom-quark mass effects. We also provide numerical results obtained with a center-of-mass energy of 10 TeV. We study the scale uncertainty of the total cross sections due to the residual renormalization- and factorization-scale dependence of the truncated perturbative series. While in the case of Z b anti-b production the scale uncertainty of the total cross section is reduced by NLO QCD corrections, the W b anti-b production process at NLO in QCD still suffers from large scale uncertainties, in particular in the inclusive case. We also perform a detailed comparison with a calculation that considers massless bottom quarks, as implemented in the Monte Carlo program MCFM. The effects of a non-zero bottom-quark mass (m_b) cannot be neglected in phase-space regions where the relevant kinematic observable, such as the transverse momentum of the bottom quarks or the invariant mass of the bottom-quark pair, are of the order of m_b. The effects on the total production cross sections are usually smaller than the residual scale uncertainty at NLO in QCD.

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arXiv2009

From the LHC to Future Colliders

Discoveries at the LHC will soon set the physics agenda for future colliders. This report of a CERN Theory Institute includes the summaries of Working Groups that reviewed the physics goals and prospects of LHC running with 10 to 300/fb of integrated luminosity, of the proposed sLHC luminosity upgrade, of the ILC, of CLIC, of the LHeC and of a muon collider. The four Working Groups considered possible scenarios for the first 10/fb of data at the LHC in which (i) a state with properties that are compatible with a Higgs boson is discovered, (ii) no such state is discovered either because the Higgs properties are such that it is difficult to detect or because no Higgs boson exists, (iii) a missing-energy signal beyond the Standard Model is discovered as in some supersymmetric models, and (iv) some other exotic signature of new physics is discovered. In the contexts of these scenarios, the Working Groups reviewed the capabilities of the future colliders to study in more detail whatever new physics may be discovered by the LHC. Their reports provide the particle physics community with some tools for reviewing the scientific priorities for future colliders after the LHC produces its first harvest of new physics from multi-TeV collisions.

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arXiv2009

Associated Production of a W Boson and One b Jet

We calculate the production of a W boson and a single b jet to next-to-leading order in QCD at the Fermilab Tevatron and the CERN Large Hadron Collider. Both exclusive and inclusive cross sections are presented. We separately consider the cross section for jets containing a single b quark and jets containing a b-anti b pair. There are a wide variety of processes that contribute, and it is necessary to include them all in order to have a complete description at both colliders.

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arXiv2008

NLO QCD corrections to Z b anti-b production with massive bottom quarks at the Fermilab Tevatron

We calculate the Next-to-Leading Order (NLO) QCD corrections to Z b anti-b production in hadronic collisions including full bottom-quark mass effects. We present results for the total cross section and the invariant mass distribution of the bottom-quark jet pair at the Fermilab Tevatron p anti-p collider. We perform a detailed comparison with a calculation that considers massless bottom quarks, as implemented in the Monte Carlo program MCFM. We find that neglecting bottom-quark mass effects overestimates the total NLO QCD cross section for Z b anti-b production at the Tevatron by about 7%, independent of the choice of the renormalization and factorization scales. Moreover, bottom-quark mass effects can impact the shape of the bottom-quark pair invariant mass distribution, in particular in the low invariant mass region.

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arXiv2007

Tevatron-for-LHC Report: Higgs

The search for Higgs bosons in both the standard model and its extensions is well under way at the Tevatron. As the integrated luminosity collected increases into the multiple inverse femptobarn range, these searches are becoming very interesting indeed. Meanwhile, the construction of the Large Hadron Collider (LHC) and its associated experiments at CERN are nearing completion. In this TeV4LHC workshop, it was realized that any experience at the Tevatron with respect to backgrounds, experimental techniques and theoretical calculations that can be verified at the Tevatron which have relevance for future measurements at the LHC were important. Studies and contributions to these efforts were made in three broad categories: theoretical calculations of Higgs production and decay mechanisms; theoretical calculations and discussions pertaining to non-standard model Higgs bosons; and experimental reviews, analyses and developments at both the Tevatron and the upcoming LHC experiments. All of these contributions represent real progress towards the elucidation of the mechanism of electroweak symmetry breaking.

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arXiv2007

Higgs boson production with one bottom quark including higher-order soft-gluon corrections

A Higgs boson produced in association with one or more bottom quarks is of great theoretical and experimental interest to the high-energy community. A precise prediction of its total and differential cross-section can have a great impact on the discovery of a Higgs boson with large bottom-quark Yukawa coupling, like the scalar (h^0 and H^0) and pseudoscalar (A^0) Higgs bosons of the Minimal Supersymmetric Standard Model (MSSM) in the region of large \tanβ. In this paper we apply the threshold resummation formalism to determine both differential and total cross-sections for b g \to bΦ(where Φ= h^0, H^0), including up to next-to-next-to-next-to-leading order (NNNLO) soft plus virtual QCD corrections at next-to-leading logarithmic (NLL) accuracy. We present results for both the Fermilab Tevatron and the CERN Large Hadron Collider (LHC).

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arXiv2006

NLO QCD corrections to W boson production with a massive b-quark jet pair at the Fermilab Tevatron p-pbar collider

We calculate the Next-to-Leading Order (NLO) QCD corrections to W-b-bbar production including full bottom-quark mass effects. We study the impact of NLO QCD corrections on the total cross section and invariant mass distribution of the bottom-quark jet pair at the Fermilab Tevatron p-pbar collider. We perform a detailed comparison with a calculation that considers massless bottom quarks. We find that neglecting bottom-quark mass effects overestimates the NLO total cross-section for W-b-bbar production at the Tevatron by about 8% independent of the choice of renormalization and factorization scale.

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arXiv2006

Hadronic Higgs Production with Heavy Quarks at the Tevatron and the LHC

We review the status of the QCD corrected cross sections and kinematic distributions for the production of a Higgs boson in association with top quark or bottom quark pairs at the Fermilab Tevatron and at the LHC. Results for b-bbar-H production are presented in the Minimal Supersymmetric Model, where the rates can be greatly enhanced relative to the Standard Model rates. We place particular emphasis on theoretical uncertainties due to renormalization and factorization scale dependence and on the uncertainties coming from the Parton Distribution Functions.

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arXiv2005

TASI 2004 Lecture Notes: Higgs Boson Physics

In these lectures I briefly review the Higgs mechanism of spontaneous symmetry breaking and focus on the most relevant aspects of the phenomenology of the Standard Model and of the Minimal Supersymmetric Standard Model Higgs bosons at both hadron and lepton colliders. Some emphasis is put on the perturbative calculation of both Higgs boson branching ratios and production cross sections, including the most important radiative corrections.

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arXiv2005

Higgs Production in Association with Bottom Quarks at Hadron Colliders

We review the present status of the QCD corrected cross sections and kinematic distributions for the production of a Higgs boson in association with bottom quarks at the Fermilab Tevatron and CERN Large Hadron Collider. Results are presented for the Minimal Supersymmetric Standard Model where, for large tan beta, these production modes can be greatly enhanced compared to the Standard Model case. The next-to-leading order QCD results are much less sensitive to the renormalization and factorization scales than the lowest order results, but have a significant dependence on the choice of the renormalization scheme for the bottom quark Yukawa coupling. We also investigate the uncertainties coming from the Parton Distribution Functions and find that these uncertainties can be comparable to the uncertainties from the remaining scale dependence of the next-to-leading order results. We present results separately for the different final states depending on the number of bottom quarks identified.

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arXiv2004

Physics Interplay of the LHC and the ILC

Physics at the Large Hadron Collider (LHC) and the International e+e- Linear Collider (ILC) will be complementary in many respects, as has been demonstrated at previous generations of hadron and lepton colliders. This report addresses the possible interplay between the LHC and ILC in testing the Standard Model and in discovering and determining the origin of new physics. Mutual benefits for the physics programme at both machines can occur both at the level of a combined interpretation of Hadron Collider and Linear Collider data and at the level of combined analyses of the data, where results obtained at one machine can directly influence the way analyses are carried out at the other machine. Topics under study comprise the physics of weak and strong electroweak symmetry breaking, supersymmetric models, new gauge theories, models with extra dimensions, and electroweak and QCD precision physics. The status of the work that has been carried out within the LHC / LC Study Group so far is summarised in this report. Possible topics for future studies are outlined.

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