First LHC data have been collected and collisions at a center-of-mass energy of 7 TeV are anticipated for the next months. The commissioning of the detectors and the re-establishment of the Standard Model in the new energy regime will be the main tasks for the experimental collaborations in the year to come. This report summarizes the measurement plans and performance expectations of the ATLAS and CMS experiments for a selected number of QCD and electroweak analyses with an emphasis on the early data taking phase. Some longer term prospects are pointed out.
The aim of this paper is to showcase the novel multilepton ($nl + E\!\!\!\!/_T$, n = 3 - 5) signals, hitherto unexplored at the LHC, arising from the heavier electroweakinos, in several generic pMSSMs at the upcoming LHC experiments. We first briefly review our old constraints on the full electroweakino sector of these models, containing both lighter and heavier sparticles, using the ATLAS trilepton data from the LHC Run I. Next we derive new stronger constraints on this sector for the first time using the ATLAS Run II data. We identify some benchmark points and explore the prospect of observi…
We report on recently computed mixed QCD-electroweak corrections to on-shell $W$ and $Z$ boson production. We use these differential predictions to estimate their impact on the $W$ boson mass determination at the LHC.
As sequel to a recent paper we examine the phenomenology of the full electroweakino sector of the pMSSM without invoking the adhoc but often employed assumption that the heavier ones are decoupled. We identify several generic models which illustrate the importance of the heavier electroweakinos and constrain them with the LHC $3l$ + ${E\!\!\!\!/_T}$ data. The constraints are usually stronger than that for decoupled heavier electroweakinos indicating that the LHC data is already sensitive to their presence. We also take into account the constraints from the observed dark matter relic density of…
The detailed study of the Higgs boson is one of the main tasks of contemporary particle physics. Gluon fusion, the main production channel of Higgs bosons at the LHC, has been successfully modelled in QCD up to $\text{N}^3\text{LO}$. To fully exploit this unprecedented theoretical effort, sub-leading contributions, such as electroweak corrections, must be investigated. I will present the analytic calculations of the gluon- and quark-induced Higgs plus jet amplitudes in mixed QCD-electroweak corrections mediated by light quarks up to order $v α^2 α_S^{3/2}$.
The dominant contribution to the Higgs production in association with bottom quark pair at the LHC is gluon-gluon fusion parton subprocess. We present a complete calculation of the next-to-leading order (NLO) electroweak (EW) corrections to this channel. The other small contributions with quarks in the initial state are calculated at tree level. We find that the NLO EW corrections can suppress the leading order (LO) contributions significantly.
We describe the program KKMC-hh, which calculates Z boson processes in hadronic collisions using coherent exclusive exponentiation (CEEX) with exact second-order photonic corrections at next-to-leading log and first-order weak vertex corrections, including initial and final state photonic radiation and initial-final interference. We describe current applications to precision forward-backward asymmetry calculations for the measurement of the electroweak mixing angle at the LHC.
We find new limits on the $λ'_{3jk}$ R-parity violating (RPV) couplings of the minimal supersymmetric standard model, using Drell-Yan differential cross sections at the LHC and electroweak precision measurements from LEP and SLC. Specifically, limits on six out of the nine $λ'_{3jk}$-couplings, with $j=1\text{ or }2$, are obtained using Drell-Yan data, with the remaining three (for $j=3$) bounded by precision electroweak data. We also update the limits on all $λ'_{ijk}$-couplings using electroweak data and find new bounds on $λ'_{132}$ and $λ'_{232}$ that are stronger than obtained elsewhere. …
We analyze the impact of the recently released CDF-II measurement of $W$ mass on the SMEFT analyses of the electroweak precision data as well as Higgs and electroweak diboson productions. We work in the Hagiwara, Ishihara, Szalapski, and Zeppenfeld basis in which eight generation-independent operators enter in the electroweak precision data at tree level and, unlike in the Warsaw basis, the analysis of that set of data constrains all the eight Wilson coefficients, without the need of combination with Higgs or electroweak diboson data results. We show that in the global analysis the determinati…
We study the impact of the recently computed mixed QCD-electroweak corrections to the production of $W$ and $Z$ bosons at the LHC on the value of the $W$ mass extracted from the transverse momentum distribution of charged leptons from $W$ decays. Using the average lepton transverse momenta in $W$ and $Z$ decays as simplified observables for the determination of the $W$ mass, we estimate that mixed QCD-electroweak corrections can shift the extracted value of the $W$ mass by up to ${\cal O}(20)~{\rm MeV}$, depending on the kinematic cuts employed to define fiducial cross sections for $Z$ and $W$…
