119220539
Potential precision of a direct measurement of the Higgs boson total width at a muon collider
In the light of the discovery of a 126 GeV Standard-Model-like Higgs boson at the LHC, we evaluate the achievable accuracies for direct measurements of the width, mass, and the $s$-channel resonant production cross section of the Higgs boson at a proposed muon collider. We find that with a beam energy resolution of $R=0.01%$ (0.003%) and integrated luminosity of $0.5\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$ ($1\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$), a muon collider would enable us to determine the Standard-Model-like Higgs width to $\ifmmode\pm\else\textpm\fi{}0.35\text{ }\text{ }\mathrm{MeV}$ ($\ifmmode\pm\else\textpm\fi{}0.15\text{ }\text{ }\mathrm{MeV}$) by combining two complementary channels of the $W{W}^{*}$ and $b\overline{b}$ final states. A non-Standard-Model Higgs with a broader width is also studied. The unparalleled accuracy potentially attainable at a muon collider would test the Higgs interactions to a high precision.
119240667
Radiative return for heavy Higgs boson at a muon collider
Higgs boson properties could be studied with a high accuracy at a muon collider via the $s$-channel resonant production. We consider the situation where the center-of-mass energy of the muon collider is off the resonance above the Higgs mass. We discuss the discovery potential for a generic heavy Higgs boson and compare different production mechanisms, including the ``radiative return,'' $Z$-boson associated production and heavy Higgs pair production. These production mechanisms do not sensitively rely on a priori knowledge of the heavy Higgs boson mass. We include various types of two-Higgs-doublet models for the comparison. We conclude that the radiative return process could provide an important option for both the heavy Higgs discovery and direct measurement of invisible decays at a high energy muon collider.
54185957
Colored resonant signals at the LHC: largest rate and simplest topology
We study the colored resonance production at the LHC in a most general approach. We classify the possible colored resonances based on group theory decomposition, and construct their effective interactions with light partons. The production cross section from annihilation of valence quarks or gluons may be on the order of 400–1000 pb at LHC energies for a mass of 1 TeV with nominal couplings, leading to the largest production rates for new physics at the TeV scale, and simplest event topology with dijet final states. We apply the new dijet data from the LHC experiments to put bounds on various possible colored resonant states. The current bounds range from 0.9 to 2.7 TeV. The formulation is readily applicable for future searches including other decay modes.
55815228
Muon Collider Higgs Factory for Snowmass 2013
Author(s): Alexahin, Y; Ankenbrandt, CM; Cline, DB; Conway, A; Cummings, MA; Benedetto, VD; Eichten, E; Gatto, C; Grinstein, B; Gunion, J; Han, T; Hanson, G; Hill, CT; Ignatov, F; Johnson, RP; Lebedev, V; Lipton, R; Liu, Z; Markiewicz, T; Mazzacane, A; Mokhov, N; Nagaitsev, S; Neuffer, D; Palmer, M; Purohit, MV; Raja, R; Striganov, S; Summers, D; Terentiev, N; Wenzel, H | Abstract: We propose the construction of, and describe in detail, a compact Muon Collider s-channel Higgs Factory.
117360716
Diagnosis of a New Neutral Gauge Boson at the LHC and ILC for Snowmass 2013
A U(1)' or Z' is generic in many scenarios of physics beyond the Standard Model, such as string theory compactifications, GUTs, extra-dimensions, compositeness, dynamical electroweak symmetry breaking, dark-sector models, etc. We study the potential of probing a TeV-scale Z' with electroweak couplings in future experiments. In particular, we focus on two scenarios: (1) If a Z' is discovered at the LHC, what is the potential of measuring its mass and width and to distinguish between benchmark models utilizing various observables, especially asymmetries, at a high luminosity LHC and the ILC. (2) If the Z' is not accessible as a clear resonance signal, what is the exclusion reach at the ILC.
119237150
Exotic decays of the 125 GeV Higgs boson
We perform an extensive survey of non-standard Higgs decays that are consistent with the 125 GeV Higgs-like resonance. Our aim is to motivate a large set of new experimental analyses on the existing and forthcoming data from the Large Hadron Collider (LHC). The explicit search for exotic Higgs decays presents a largely untapped discovery opportunity for the LHC collaborations, as such decays may be easily missed by other searches. We emphasize that the Higgs is uniquely sensitive to the potential existence of new weakly coupled particles and provide a unified discussion of a large class of both simplified and complete models that give rise to characteristic patterns of exotic Higgs decays. We assess the status of exotic Higgs decays after LHC Run 1. In many cases we are able to set new nontrivial constraints by reinterpreting existing experimental analyses. We point out that improvements are possible with dedicated analyses and perform some preliminary collider studies. We prioritize the analyses according to their theoretical motivation and their experimental feasibility. This document is accompanied by a website that will be continuously updated with further information: this http URL
123449156
Search for an invisibly-decaying Higgs boson at LEP
Abstract A search for a Higgs boson produced in e + e − collisions in association with a Z boson and decaying into invisible particles is performed. Data collected at LEP with the L3 detector at centre-of-mass energies from 189 to 209 GeV are used, corresponding to an integrated luminosity of 0.63 fb −1 . Events with hadrons, electrons or muons with visible masses compatible with a Z boson and missing energy and momentum are selected. They are consistent with the Standard Model expectations. A lower limit of 112.3 GeV is set at 95% confidence level on the mass of the invisibly-decaying Higgs boson in the hypothesis that its production cross section equals that of the Standard Model Higgs boson. Relaxing this hypothesis, upper limits on the production cross section are derived.
209834184
Measurement of genuine three-particle Bose-Einstein correlations in hadronic Z decay
We measure three-particle Bose-Einstein correlations in hadronic Z decay with the L3 detector at LEP. Genuine three-particle Bose-Einstein correlations are observed. By comparing two- and three-particle correlations we find that the data are consistent with fully incoherent pion production.
204860499
Flavour independent search for neutral Higgs bosons at LEP
Abstract A flavour independent search for the CP-even and CP-odd neutral Higgs bosons h and A is performed in 624 pb −1 of data collected with the L3 detector at LEP at centre-of-mass energies between 189 and 209 GeV . Higgs boson production through the e + e − →Zh and the e + e − →hA processes is considered and decays of the Higgs bosons into hadrons are studied. No significant signal is observed and 95% confidence level limits on the hZZ and hAZ couplings are derived as a function of the Higgs boson masses. Assuming the Standard Model cross section for the Higgs-strahlung process and a 100% branching fraction into hadrons, a 95% confidence level lower limit on the mass of the Higgs boson is set at 110.3 GeV.
109503383
Introduction to BESIII EMC sub-trigger system
Abstract The Electromagnetic Calorimeter (EMC) sub-trigger system is one of the important parts of the trigger system of the BESIII spectrometer. Together with the conditions from the other sub-trigger systems, cluster-related and energy-related trigger conditions are provided to the Global Trigger system for effective selection of events interested and rejection of backgrounds. Total two types of PCB boards are designed to implement the whole functions, which are Trigger Cell and energy Block Adding (TCBA) and Energy Adding and Cluster Counting (EACC). Simulations and hardware arrangement of the EMC sub-trigger system are introduced in this paper.
55251857
Connecting the direct detection of dark matter with observation of sparticles at the LHC
An analysis is given connecting event rates for the direct detection of neutralino dark matter with the possible signatures of supersymmetry at the LHC. It is shown that if an effect is seen in the direct detection experiments at a level of O(10(-44)) cm(2) for the neutralino-proton cross section, then within the minimal supergravity grand unified model the next heavier particle above the neutralino is either a stau, a chargino, or a CP odd/CP even (A/H) Higgs boson. Further, the collider analysis shows that models with a neutralino-proton cross section at the level of (1 - 5) x 10(-44) cm(2) could be probed with as little as 1 fb(-1) of integrated luminosity at the LHC at root s = 7, 10 TeV. The most recent limit from the five tower CDMS II result on weakly interacting massive particle-nucleon cross section is discussed in this context. It is argued that the conclusions of the analysis given here are more broadly applicable with inclusion of nonuniversalities in the supergravity grand unified models.