G. Altarelli
I present a concise review of where we stand in particle physics today. First, I will discuss QCD, then the electroweak sector and finally the motivations and the avenues for new physics beyond the Standard Model.
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I review the status of theoretical calculations relevant for electroweak physics at the Tevatron and LHC and discuss future directions. I also give a brief overview of current electroweak data and discuss future expectations.
We briefly review the status of high precision QCD predictions available for LHC processes, focusing on corrections beyond NLO and ways to make the latter available in a convenient format. As a phenomenological example we discuss the two-loop corrections to Higgs boson pair production in gluon fusion.
We review status and prospects of searches for the charged Higgs boson of 2-Higgs Doublet Models of all Yukawa types at the Large Hadron Collider
I review the status of supersymmetry after the 2011 LHC search results. I concentrate in particular on interpretations beyond the conventional CMSSM, including i) natural SUSY with light stops, and ii) the so-called phenomenological MSSM, which is a general parametrization of the MSSM at the weak scale, without boundary conditions imposed by specific SUSY breaking schemes. We will see that the current searches are not yet sensitive to some of the theoretically most interesting scenarios.
We discuss the current status of LHC physics from the perspective of precision theory predictions for the attendant QCD and EW higher order corrections. We focus on the interplay between the available data and the predictions for these data viewed in the context of the establishment of baselines for what is needed to exploit fully the discovery potential of the existing LHC data and the data expected by the end of the second LHC run (i.e., 300fb$^{-1}$). We conclude that significant improvement in the currently used theoretical predictions will be mandatory. Possible strategies to achieve such…
Discovering the Higgs boson is one of the primary goals of both the Tevatron and the Large Hadron Collider (LHC). The present status of the Higgs search is reviewed and future prospects for discovery at the Tevatron and LHC are considered. This talk focuses primarily on the Higgs boson of the Standard Model and its minimal supersymmetric extension. Theoretical expectations for the Higgs boson and its phenomenological consequences are reviewed.
Weak gauge boson pair production is an important process at the LHC because it probes the non-Abelian structure of electroweak interactions and it is a background process for many new physics searches, and with enough statistics we can perform comparisons between measurements and theoretical calculations for different but correlated observables. In these proceedings, we present a theoretical status including state-of-the-art results from recent calculations of higher-order QCD and electroweak corrections.
The abundant amount of data to be collected by the ATLAS and CMS collaborations in future runs of the Large Hadron Collider at CERN opens up a new era of precision physics. Some of the most prominent precision observables are related to processes with one or more jets in the final state. In order to fully exploit the potential of the LHC and the HL-LHC, it is imperative to make theoretical predictions at the level of accuracy that matches or even exceeds that of the upcoming measurements. In this talk we present a review of the status of theoretical predictions including NNLO QCD corrections f…
We provide an update of the global fits of the couplings of the 125.5 GeV Higgs boson using all publicly available experimental results from Run-1 of the LHC as per Summer 2014. The fits are done by means of the new public code Lilith 1.0. We present a selection of results given in terms of signal strengths, reduced couplings, and for the Two-Higgs-Doublet Models of Type I and II.
The Inert Doublet Model (IDM) is one of the simplest extensions of the Standard Model that can provide a viable dark matter (DM) candidate. Despite its simplicity, it predicts a versatile phenomenology both for cosmology and for the Large Hadron Collider. We briefly summarize the status of searches for IDM dark matter in direct DM detection experiments and the LHC, focusing on the impact of the latter on the model parameter space. In particular, we discuss the consequences of the Higgs boson discovery as well as those of searches for dileptons accompanied by missing transverse energy during th…
We discuss the result with full mass dependence for the virtual NNLO QCD corrections to the W boson pair production in the quark-anti-quark annihilation channel. We also report on our progress regarding the treatment of the double-real radiative corrections which, along with the virtual-real corrections, are the other two necessary ingredients for a theoretical prediction of the total cross section for W+ W- production to NNLO accuracy.
Neutrino Physics at the LHC: Status and Prospects
本文综述LHC上现有及拟建的中微子探测器，介绍FASER和SND@LHC首次观测到LHC中微子的突破成果，总结该领域在多方向的物理研究潜力。
Searching for two-body resonance decays is a central component of the high energy physics energy frontier research program. While many of the possibilities are covered when the two bodies are Standard Model (SM) particles, there are still significant gaps. If one or both of the bodies are themselves non-SM particles, there is very little coverage from existing searches. We review the status of two-body searches and motivate the need to search for the missing combinations. It is likely that the search program of the future will be able to cover all possibilities with a combination of dedicated …
We present the elements of the IR-improved DGLAP-CS theory as it relates to the new MC friendly exponentiated scheme for precision calculation of higher order corrections to LHC physics in which IR singularities from both QED and QCD are canceled to all orders in alpha and in alpha_s simultaneously in the presence of rigorous shower/ME matching. We present the first MC data comparing the implied new showers themselves with the standard ones using the HERWIG6.5 MC event generator as a test case at LHC energies. As expected, the IR-improved shower re-populates lower values of the energy fraction…
An important experiment for cosmic ray physics is going to be conducted with the colliding proton beams of the CERN LHC. The equivalent energy of the 14 TeV center of mass energy of the colliding proton beams in the LHC is 1017eV in the laboratory frame. Two small electromagnetic calorimeters have been installed at zero degree collision angle +/-140m from the interaction point IP1. The calorimeters measure the energies and the positions of the axes of showers produced by forward neutral particles created in the proton-proton collisions. The shower calorimeters are therefore able to measure the…
We discuss the current status of theoretical and experimental constraints on the real Higgs singlet extension of the Standard Model. For the second neutral (non-standard) Higgs boson we consider the full mass range from 1 GeV to 1 TeV accessible at past and current collider experiments. We separately discuss three scenarios, namely, the case where the second Higgs boson is lighter than, approximately equal to, or heavier than the discovered Higgs state at around 125 GeV. We investigate the impact of constraints from perturbative unitarity, electroweak precision data with a special focus on hig…
In this talk we review the GOLEM approach to one-loop calculations and present an automated implementation of this technique. This method is based on Feynman diagrams and an advanced reduction of one-loop tensor integrals which avoids numerical instabilities. We have extended our one-loop integral library golem95 with an automated one-loop matrix element generator to compute the virtual corrections of the process $q\bar{q}\to b\bar{b}b\bar{b}$. The implementation of the virtual matrix element has been interfaced with tree-level Monte Carlo programs to provide the full result for the above proc…
Rare decays of heavy-flavoured particles provide an ideal laboratory to look for deviations from the Standard Model, and explore energy regimes beyond the LHC reach. Decays proceeding via electroweak penguin diagrams are excellent probes to search for New Physics, and $b \to s \ell^{+}\ell^{-}$ processes are particularly interesting since they give access to many observables such as branching fractions, asymmetries and angular observables. Recent results from the LHCb experiment are reviewed.
In this article, we briefly review the recent progress related to extracting the quark-gluon plasma (QGP) specific shear viscosity from the flow data measured at Relativistic Heavy-Ion Collider (RHIC) and the Large Hadron Collider (LHC).
We present a status report on the indirect searches for New Physics performed by means of heavy flavour decays. Particular attention is devoted to the recent experimental results in B and charm physics obtained by the LHC experiments. The implications of these results for physics beyond the Standard Model are discussed both in general terms and by means of a few specific examples.
Unequal strengths of boundary localised terms lead to non-conservation of the Kaluza-Klein (KK) parity in the 4 + 1 Universal Extra Dimensional model. Consequently the first excited KK-partners of Standard Model particles are not stable by any symmetry. In this article using the latest 13 TeV Large Hadron Collider (LHC) results, we revisit the resonant production of first KK-excitations of the neutral gauge bosons ($G^1$, $B^1\ \textrm{and} \ W_3^1$) and their subsequent decay. {\it Specifically $G^1$ (first KK-excitation of gluon) decays to $t\bar{t}$ pair and $B^1/W_3^1$ (first KK-excitation…
The LHC data have confirmed the Standard Model as the correct theory at the electroweak scale. It successfully explains the experimental results with high precision and all its ingredients, including the Higgs boson, have been finally verified. At the same time, the negative searches for signals of new phenomena challenge our previous theoretical wisdom on new-physics scenarios.
This paper presents the latest development at CERN, concentrating on the status of the LHC and the strategy for future linear colliders. The immediate plans include the exploitation of the LHC at its design luminosity and energy as well as upgrades to the LHC (luminosity and energy) and to its injectors. This may be complemented by a linear electron-positron collider, based on the technology being developed by the Compact Linear Collider and by the International Linear Collider and/or by a high-energy electron-proton collider. This contribution describes the various future directions, all of w…
In the context of minimal supersymmetric standard model (MSSM), we discuss the possibility of the lightest Higgs boson with mass $M_h = 98 $ GeV to be consistent with the $2.3σ$ excess observed at the LEP in the decay mode $e^+e^- \to Zh$, with $h \to b {\bar b}$. In the same region of the MSSM parameter space, the heavier Higgs boson $(H)$ with mass $M_H \sim 125 $ GeV is required to be consistent with the latest data on Higgs coupling measurements at the end of 7 + 8 TeV LHC run with $25{\rm fb}^{-1}$ of data. While scanning the MSSM parameter space, we impose constraints coming from flavour…
Searches for Beyond the Standard Model Higgs processes in the context of Minimal Supersymmetric Standard Model and Next to MSSM are presented. The results are based on the first LHC run of pp collision data recorded by the ATLAS and CMS experiments at the CERN Large Hadron Collider at centre-of-mass energies of 7 and 8 TeV, corresponding to integrated luminosities of about 5 and 20 fb$^{-1}$ respectively. Current searches constrain large parts of the parameter space. No evidence for BSM Higgs is found.
A possible feature of the inert doublet model (IDM) is to provide a dark matter candidate together with an alteration of both direct and indirect collider constraints that allow for a heavy Higgs boson. We study the IDM in light of recent results from Higgs searches at the Large Hadron Collider (LHC) in combination with dark matter direct detection limits from the XENON experiment. We ask under what conditions the IDM can still accommodate a heavy Higgs boson. We find that IDM scenarios with a Higgs boson in the mass range 160-600 GeV are ruled out only when all experimental constraints are co…
LHCb is a dedicated detector for b and c physics at the LHC. I will present a concise review of the detector design and expected performance together with some first results on the commissioning of the different sub-systems based on cosmic data and particle beams delivered by the LHC during the summer of 2008. The experiment is ready to exploit first data expected from the LHC. An integrated luminosity of ~0.3fb-1, which should be collected during the first year of physics running, will already allow LHCb to perform a number of very significant mesurements with the potential of revealing New P…
The LHC has collided protons on protons at center-of-mass energies of 7 and 8 TeV between 2010-2012, referred to as the Run I period. We review the current status of searches for new physics beyond the Standard Model at the end of Run I by the ATLAS and CMS experiments, limited to the 8 TeV search results published or submitted for publication as of the end of February 2014. We discuss some of the implications of these searches on the existence of TeV scale new physics, with a special focus on two open questions: the hierarchy problem, and the nature of dark matter. Finally, we give an outlook…
Now that the Higgs boson has been observed by the ATLAS and CMS experiments at the LHC, the next important step would be to measure accurately its properties to establish the details of the electroweak symmetry breaking mechanism. Among the measurements which need to be performed, the determination of the Higgs self-coupling in processes where the Higgs boson is produced in pairs is of utmost importance. In this paper, we discuss the various processes which allow for the measurement of the trilinear Higgs coupling: double Higgs production in the gluon fusion, vector boson fusion, double Higgs-…
In this talk, I overview the recent progress on the global analysis of nuclear parton distribution functions (nuclear PDFs). After first introducing the contemporary fits, the analysis procedures are quickly recalled and the ambiguities in the use of experimental data outlined. Various nuclear-PDF parametrizations are compared and the main differences explained. The effects of nuclear PDFs in the LHC p-Pb hard-process observables are discussed and some future prospects sketched.
We summarize the status of QCD corrections for SM Higgs boson production at hadron colliders and briefly sketch the main search strategies at the LHC.
We investigate the prospects for Central Exclusive Diffractive (CED) production of MSSM Higgs bosons at the LHC using forward proton detectors (FPD) proposed to be installed 220 m and 420 m from ATLAS and CMS detectors. We summarize the situation after the first and very successful data taking period of the LHC. The discovery of a Higgs boson and results from searches for additional MSSM Higgs bosons from the ATLAS and CMS, have recently led to a proposal of new low-energy MSSM benchmark scenarios. The CED signal cross section for the process H -> bb and its backgrounds are estimated in these …
In the natural realization of the Next-to-minimal Supersymmetric Standard Model, Higgsinos tend to be lighter than about several hundred GeVs, which can induce detectable leptonic signals at the LHC as well as large DM-nucleon scattering cross section. We explore the constraints from the direct searches for electroweakino and slepton at the LHC Run II and the latest DM direct detection experiments on the scenario with low fine tuning indicator $Δ_{Z/h} \leq 50$. We find that these experiments are complementary to each other in excluding the scenario, and as far as each kind of experiment is co…
Now that a Higgs boson has been discovered at the LHC, measuring its couplings to other particles is the next important step. In order to probe the electroweak symmetry breaking mechanism at its core it is crucial to reconstruct the scalar potential and hence measure the triple Higgs coupling at the LHC. We present a review of the main Standard Model Higgs boson pair production mechanisms in which the triple Higgs coupling plays a role and present the latest phenomenological analyses in view of a high luminosity LHC. One example of an analysis in the Two-Higgs-Doublet model will also be given …
Supersymmetry (SUSY) is a complete and renormalisable candidate for an extension of the Standard Model. At an energy scale not too far above the electroweak scale it would solve the hierarchy problem of the SM Higgs boson, dynamically explain electroweak symmetry breaking, and provide a dark-matter candidate. Since it doubles the Standard Model degrees of freedom, SUSY predicts a large number of additional particles, whose properties and effects on precision measurements can be explicitly predicted in a given SUSY model. In this review the motivation for SUSY is outlined, the various searches …
We present some highlights on the complementaries of the Higgs and SUSY searches at the LHC, using the 8 and 13 TeV results. In particular, we discuss the constraints that can be obtained on the MSSM parameters by the determination of the Higgs boson mass and couplings. In addition, we investigate the interplay with heavy Higgs searches, and evaluate how higher LHC luminosities and a future linear collider can help probing the pMSSM Higgs sector and reconstructing the underlying parameters.
We show that the predictivity of general gauge mediation (GGM) with TeV-scale stops is greatly increased once the Higgs mass constraint is imposed. The most notable results are a strong lower bound on the mass of the gluino and right-handed squarks, and an upper bound on the Higgsino mass. If the mu-parameter is positive, the wino mass is also bounded from above. These constraints relax significantly for high messenger scales and as such long-lived NLSPs are favored in GGM. We identify a small set of most promising topologies for the neutralino/sneutrino NLSP scenarios and estimate the impact …
We study limits from dilepton searches on leptoquark completions to the Standard Model in the parameter space motivated by anomalies in the $b \rightarrow s$ sector. After a full Run-2 analysis by LHCb, the disparity in lepton flavour violation has disappeared. However, the mismatch in angular distributions as well as in $B_s \rightarrow μ^+ μ^-$ partial width is still unresolved and still implies a possible new physics contribution. We probe three models of leptoquarks -- scalar models $S_3$ and $R_2$ as well as vector leptoquark model $U_1$ using non-resonant dilepton searches to place limit…
In this talk I discuss the status and future prospects of testing the Higgs self-couplings at the High Luminosity LHC (HL-LHC) as well as several Beyond Standard Model (BSM) scenarios that could be probed via Higgs pair production in the coming years.
While LHC has discovered a very Standard Model-like Higgs boson of mass m_h~ 125 GeV, no solid signal for physics beyond the Standard Model has emerged so far at LHC or at WIMP seach experiments. For the case of weak scale supersymmetry (SUSY), LHC has found rather generally that gluinos are beyond about 2.2 TeV whilst top squark must lie beyond 1.1 TeV. These limits contradict older simplistic notions of naturalness that emerged in the 1980s-1990s, leading to the rather pessimistic view that SUSY is now excluded except for perhaps some remaining narrow corners of parameter space. Yet, this pi…
While most BSM searches at the LHC focus on heavy new states, the NMSSM contains the possibility of new light states that have escaped detection due to their singlet nature. Here we focus on light pseudoscalars, investigating the parameter space impact of recent LHC searches for such light states stemming from the decay of the 125 GeV Higgs boson. It is shown that, though direct searches can not yet compete with the requirement of the 125 GeV scalar having SM-like couplings, the searches are touching the allowed parameter space and should make a phenomenological impact in the near future.
Motivated by the latest results of the LHC Run-2 and LUX experiments, we examine the status of the constrained minimal supersymmetric standard model (CMSSM) by performing a global fit. We construct a likelihood function including the electroweak precision observables, $B$-physics measurements, LHC Run-1 and -2 data of SUSY direct searches, Planck observation of the dark matter relic density and the combined LUX Run-3 and -4 detection limits. Based on the profile likelihood functions of 1 billion samples, we obtain the following observations: (i) The stau coannihilation region has been mostly e…
We summarize the status of various supersymmetric models in view of the existing LHC data. A particular focus is on the implications of the measured Higgs mass on these models which gives important constraints. We consider here minimal and non-mininal supersymmetric extension of the Standard Model.
The new minimal supersymmetric standard model (nMSSM), a variant of the general next to minimal supersymmetric standard model (NMSSM) without $Z_3$ symmetry, features a naturally light singlino with a mass below 75 GeV. In light of the new constraints from LHC Run-1 on the Higgs couplings, sparticles searches and flavour observables, we define the parameter space of the model which is compatible with both collider and dark matter (DM) properties. Among the regions compatible with these constraints, implemented through NMSSMTools, SModelS and MadAnalysis 5, only one with a singlino lightest sup…
I present a concise review of where we stand in particle physics today. First, I will discuss the status of the Standard Model, its open problems and the expected answers from the LHC. Then I will briefly review the avenues for New Physics that can be revealed by the LHC.
The ATLAS and CMS experiments at the Large Hadron Collider (LHC) at CERN have searched for signals of new physics, in particular for supersymmetry. The data collected until 2012 at center-of-mass energies of 7 and 8 TeV and integrated luminosities of 5 fb^-1 and 20 fb^-1, respectively, agree with the expectation from standard model processes. Constraints on supersymmetry have been calculated and interpreted in different models. Limits on supersymmetry particle masses at the TeV scale have been derived and interpreted generally in the context of simplified model spectra. The constrained minimal…
The discovery of the Standard Model (SM) or supersymmetric (SUSY) Higgs bosons belongs to the main endeavors of the Large Hadron Collider (LHC). In this article the status of the signal and background calculations for Higgs boson production at the LHC is reviewed.
I present a brief discussion of the different approaches to the study initial state effects in heavy ion collisions in view of the recent results from Pb+Pb and p+p collisions at the LHC.
We briefly review the current status of theoretical calculations for Higgs production at hadron colliders within the Standard Model. We focus on the main production mechanisms and decay modes at the Tevatron and the LHC.
We thoroughly investigate the current status of supersymmetry in light of the latest searches at the LHC, using General Gauge Mediation (GGM) as a well-motivated signature generator that leads to many different simplified models. We consider all possible promptly-decaying NLSPs in GGM, and by carefully reinterpreting the existing LHC searches, we derive limits on both colored and electroweak SUSY production. Overall, the coverage of GGM parameter space is quite good, but much discovery potential still remains even at 7 TeV. We identify several regions of parameter space where the current searc…
Using the MC Herwiri1.031, we present the current status of the comparisons with LHC data of the predictions of our approach of exact amplitude-based resummation for precision QCD calculations.
In these lectures I start by briefly reviewing the status of the electroweak theory, in the Standard Model and beyond. I then discuss the motivation and the possible avenues for new physics, on the brink of the LHC start.
The present status of theoretical calculations for signal and background processes relevant to the Higgs boson search at the LHC is reviewed, with special emphasis on recent developments. The issue of Higgs properties determination at the LHC is addressed.
The second period of datataking at the Large Hadron Collider (LHC) has provided a large dataset of proton-proton collisions that is unprecedented in terms of its centre-of-mass energy of 13 TeV and integrated luminosity of almost 140 fb$^{-1}$. These data constitute a formidable laboratory for the search for new particles predicted by models of supersymmetry. The analysis activity is still ongoing, but a host of results on supersymmetry has already been released by the general purpose LHC experiments ATLAS and CMS. In this paper, we provide a map into this remarkable body of research, which sp…
I review the status of the general-purpose Monte Carlo event generators for the LHC, with emphasis on areas of recent physics developments. There has been great progress, especially in multi-jet simulation, but I mention some question marks that have recently arisen.
I review the current status of the nucleon PDFs determined from global fits with emphasis on the impact of recent experimental data and the remaining theoretical challenges.
We discuss the status of the theoretical predictions of some interesting b-physics observables that are sensitive to New Physics and can be measured at the LHC.
I review the status of the comparisons between a few measurements at hadronic colliders and perturbative QCD predictions, which emphasize the need for improving the current computations. Such improvements will be mandatory for a satisfactory understanding of high-energy collisions at the LHC
A brief overview of the main highlights discussed at ICHEP 2014 is presented. The experimental data confirm that the scalar boson discovered at the LHC couples to other particles as predicted in the Standard Model. This constitutes a great success of the present theoretical paradigm, which has been confirmed as the correct description at the electroweak scale. At the same time, the negative searches for signals of new phenomena tightly constrain many new-physics scenarios, challenging previous theoretical wisdom and opening new perspectives in fundamental physics. Fresh ideas are needed to fac…
We present the current status of the comparisons with the respective data of the predictions of our approach of exact amplitude-based resummation in quantum field theory as applied to precision QCD calculations as needed for LHC physics. The agreement between the theoretical predictions and the data exhibited continues to be encouraging.
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