Journal of High Energy Physics

http://link.springer.com/journal/13130

List of Papers (Total 10,412)

Performance of jet substructure techniques for large-R jets in proton-proton collisions at \( \sqrt{s}=7 \) TeV using the ATLAS detector

This paper presents the application of a variety of techniques to study jet substructure. The performance of various modified jet algorithms, or jet grooming techniques, for several jet types and event topologies is investigated for jets with transverse momentum larger than 300 GeV. Properties of jets subjected to the mass-drop filtering, trimming, and pruning algorithms are...

First observation of the decay \( B_c^{+}\to {J \left/ {{\psi {K^{+}}}} \right.} \)

The decay \( B_c^{+}\to {J \left/ {{\psi {K^{+}}}} \right.} \) is observed for the first time using a data sample, corresponding to an integrated luminosity of 1.0 fb−1, collected by the LHCb experiment in pp collisions at a centre-of-mass energy of 7 TeV. A yield of 46 ± 12 events is reported, with a significance of 5.0 standard deviations. The ratio of the branching fraction of...

A strongly coupled zig-zag transition

The zig-zag symmetry transition is a phase transition in 1D quantum wires, in which a Wigner lattice of electrons transitions to two staggered lattices. Previous studies model this transition as a Luttinger liquid coupled to a Majorana fermion. The model exhibits interesting RG flows, involving quenching of velocities in subsectors of the theory. We suggest an extension of the...

Classical tau-function for quantum spin chains

For an arbitrary generalized quantum integrable spin chain we introduce a “master T -operator” which represents a generating function for commuting quantum transfer matrices constructed by means of the fusion procedure in the auxiliary space. We show that the functional relations for the transfer matrices are equivalent to an infinite set of model-independent bilinear equations...

Almost BPS but still not renormalized

A key feature of BPS multi-center solutions is that the equations controlling the positions of these centers are not renormalized as one goes from weak to strong coupling. In particular, this means that brane probes can capture the same information as the fully back-reacted supergravity solution. We investigate this non-renormalization property for non-supersymmetric, extremal...

On gauge invariance and minimal coupling

The principle of minimal coupling has been used in the study of Higgs boson interactions to argue that certain higher dimensional operators in the low-energy effective theory generalization of the Standard Model are suppressed by loop factors, and thus smaller than others. It also has been extensively used to analyze beyond-the-Standard-Model theories. We show that in field...

Here be dragons: the unexplored continents of the CMSSM

The Higgs boson mass and the abundance of dark matter constrain the CMSSM/mSUGRA supersymmetry breaking inputs. A complete map of the CMSSM that is consistent with these two measured quantities is provided. Various “continents”, consisting of non-excluded models, can be organized by their dark matter dynamics. The following mechanisms manifest: well-tempering, resonant pseudo...

Multiplicity dependence of two-particle azimuthal correlations in pp collisions at the LHC

We present the measurements of particle pair yields per trigger particle obtained from di-hadron azimuthal correlations in pp collisions at \( \sqrt{s} \) = 0.9, 2.76, and 7 TeV recorded with the ALICE detector. The yields are studied as a function of the charged particle multiplicity. Taken together with the single particle yields the pair yields provide information about parton...

Measurement of charm fragmentation fractions in photoproduction at HERA

The production of D 0, D *+, D +, \( D_s^{+} \) and \( \Lambda_c^{+} \) charm hadrons and their antiparticles in ep scattering at HERA has been studied with the ZEUS detector, using a total integrated luminosity of 372 pb−1. The fractions of charm quarks hadronising into a particular charm hadron were derived. In addition, the ratio of neutral to charged D-meson production rates...

Constraining Inert Dark Matter by R γγ and WMAP data

We discuss the constraints on Dark Matter coming from the LHC Higgs data and WMAP relic density measurements for the Inert Doublet Model, which is one of the simplest extensions of the Standard Model providing a Dark Matter candidate. We found that combining the diphoton rate R γγ and the Ω DM h 2 data one can set strong limits on the parameter space of the Inert Doublet Model...

Noncommutative gauge theories on \( \mathbb{R}_{\theta}^2 \) as matrix models

We study a class of noncommutative gauge theory models on 2-dimensional Moyal space from the viewpoint of matrix models and explore some related properties. Expanding the action around symmetric vacua generates non local matrix models with polynomial interaction terms. For a particular vacuum, we can invert the kinetic operator which is related to a Jacobi operator. The resulting...

Grassmannian connection between three- and four-qubit observables, Mermin’s contextuality and black holes

We invoke some ideas from finite geometry to map bijectively 135 heptads of mutually commuting three-qubit observables into 135 symmetric four -qubit ones. After labeling the elements of the former set in terms of a seven-dimensional Clifford algebra, we present the bijective map and most pronounced actions of the associated symplectic group on both sets in explicit forms. This...

Mathieu moonshine and \( \mathcal{N}=2 \) string compactifications

There is a ‘Mathieu moonshine’ relating the elliptic genus of K3 to the sporadic group M 24. Here, we give evidence that this moonshine extends to part of the web of dualities connecting heterotic strings compactified on K3 × T 2 to type IIA strings compactified on Calabi-Yau threefolds. We demonstrate that dimensions of M 24 representations govern the new supersymmetric index of...

Holographic isotropization linearized

The holographic isotropization of a highly anisotropic, homogeneous, strongly coupled, non-Abelian plasma was simplified in ref. [1] by linearizing Einstein’s equations around the final, equilibrium state. This approximation reproduces the expectation value of the boundary stress tensor with a 20% accuracy. Here we elaborate on these results and extend them to observables that...

Towards an understanding of jet substructure

We present first analytic, resummed calculations of the rates at which wide-spread jet substructure tools tag QCD jets. As well as considering trimming, pruning and the mass-drop tagger, we introduce modified tools with improved analytical and phenomenological behaviours. Most taggers have double logarithmic resummed structures. The modified mass-drop tagger is special in that it...

More on the hypercharge portal into the dark sector

If the hidden sector contains more than one U(1) groups, additional dim-4 couplings (beyond the kinetic mixing) between the massive U(1) fields and the hypercharge generally appear. These are of the form similar to the Chern-Simons interactions. We study the phenomenology of such couplings including constraints from laboratory experiments and implications for dark matter. The...

Unitarity and fuzzball complementarity: “Alice fuzzes but may not even know it!”

We investigate the recent black hole firewall argument. For a black hole in a typical state we argue that unitarity requires every quantum of radiation leaving the black hole to carry information about the initial state. An information-free horizon is thus inconsistent with unitary at every step of the evaporation process. The required horizon-scale structure is manifest in the...

Isolating prompt photons with narrow cones

We discuss the isolation of prompt photons in hadronic collisions by means of narrow isolation cones and the QCD computation of the corresponding cross sections. We reconsider the occurence of large perturbative terms with logarithmic dependence on the cone size and their impact on the fragmentation scale dependence. We cure the apparent perturbative violation of unitarity for...

Physics performance for scalar electron, scalar muon and scalar neutrino searches at \( \sqrt{s} \) = 3 TeV and 1.4 TeV at CLIC

The determination of scalar lepton and gaugino masses is an important part of the programme of spectroscopic studies of Supersymmetry at a high energy e + e − linear collider. In this article we present results of a study of the processes: e + e − → \( \widetilde{e}_R^{+}\widetilde{e}_R^{-} \) → e + e − \( \widetilde{\chi}_1^0\widetilde{\chi}_1^0 \), e + e − → \( \widetilde{\mu...

Searches for \( B_{(s)}^0\ \to {J \left/ {{\psi p}} \right.}\overline{p} \) and B + → J/ψ p \( \overline{p} \) π + decays

The results of searches for \( B_{(s)}^0\to {J \left/ {\psi\ p } \right.}\overline{p} \) and B + → J/ψ p \( \overline{p} \)π+ decays are reported. The analysis is based on a data sample, corresponding to an integrated luminosity of 1.0 fb−1 of pp collisions, collected with the LHCb detector. An excess with 2.8 σ significance is seen for the decay \( B_s^0\to {J \left/ {\psi\ p...

Light stops emerging in WW cross section measurements?

Recent ATLAS and CMS measurements show a slight excess in the W + W − cross section measurement. While still consistent with the Standard Model within 1−2-σ, the excess could be also a first hint of physics beyond the Standard Model. We argue that this effect could be attributed to the production of scalar top quarks within supersymmetric models. The stops of \( {m_...

Measurement of B meson production cross-sections in proton-proton collisions at \( \sqrt{s}=7 \) TeV

AbstractThe production cross-sections of B mesons are measured in pp collisions at a centre-of-mass energy of 7 TeV, using data collected with the LHCb detector corresponding to a integrated luminosity of 0.36 fb−1. The B +, B 0 and \( B_s^0 \) mesons are reconstructed in the exclusive decays B + → J/ψK +, B 0 → J/ψK *0 and \( B_s^0\to {J \left/ {{\psi \phi }} \right.} \), with J...

Quarter-BPS AdS 5 solutions in M-theory with a T 2 bundle over a Riemann surface

We study and classify quarter-BPS AdS 5 systems in M-theory, whose internal six-dimensional geometry is a T 2 bundle over a Riemann surface and two interval directions. The general system presented, provides a unified description of all known AdS 5 solutions in M-theory. These systems are governed by two functions, one that corresponds to the conformal factor of the Riemann...

Superstring amplitudes and the associator

We investigate a pattern in the α′ expansion of tree-level open superstring amplitudes which correlates the appearance of higher depth multiple zeta values with that of simple zeta values in a particular way. We rephrase this relationship in terms of the coaction on motivic multiple zeta values and show that the pattern takes a very simple form, which can be simply explained by...