The European Physical Journal C

http://link.springer.com/journal/10052

List of Papers (Total 3,408)

Revisit assignments of the new excited \(\Omega _c\) states with QCD sum rules

In this article, we distinguish the contributions of the positive parity and negative parity \(\Omega _c\) states, study the masses and pole residues of the 1S, 1P, 2S and 2P \(\Omega _c\) states with the spin \(J=\frac{1}{2}\) and \(\frac{3}{2}\) using the QCD sum rules in a consistent way, and we revisit the assignments of the new narrow excited \(\Omega _c^0\) states. The ...

S- and T-self-dualities in dilatonic \(f(R)\) theories

We search for theories, in general spacetime dimensions, that would incorporate a dilaton and higher powers of the scalar Ricci curvature such that they have exact S- or T-self-dualities. The theories we find are free of Ostrogradsky instabilities. We also show that within the framework we are confining ourselves, a theory of the form mentioned above cannot have both T- and ...

Spectroscopic parameters and decays of the resonance \(Z_b(10610)\)

The resonance \(Z_b(10610)\) is investigated as the diquark–antidiquark \( Z_b=[bu][\overline{bd}]\) state with spin–parity \(J^{P}=1^{+}\). The mass and current coupling of the resonance \(Z_b(10610)\) are evaluated using QCD two-point sum rule and taking into account the vacuum condensates up to ten dimensions. We study the vertices \(Z_b\Upsilon (nS)\pi \ (n=1,2,3)\) by applying ...

Impact of the heavy-quark matching scales in PDF fits

We investigate the impact of displaced heavy-quark matching scales in a global fit. The heavy-quark matching scale \(\mu _{m}\) determines at which energy scale \(\mu \) the QCD theory transitions from \(N_{F}\) to \(N_{F}+1\) in the variable flavor number scheme (VFNS) for the evolution of the parton distribution functions (PDFs) and strong coupling \(\alpha _S(\mu )\). We study ...

Jet-associated resonance spectroscopy

We present a model-independent study aimed at characterising the nature of possible resonances in the jet-photon or jet-Z final state at hadron colliders. Such resonances are expected in many models of compositeness and would be a clear indication of new physics. At leading order, in the narrow width approximation, the matrix elements are parameterised by just a few constants ...

Finite entanglement entropy and spectral dimension in quantum gravity

What are the conditions on a field theoretic model leading to a finite entanglement entropy density? We prove two very general results: (1) Ultraviolet finiteness of a theory does not guarantee finiteness of the entropy density; (2) If the spectral dimension of the spatial boundary across which the entropy is calculated is non-negative at all scales, then the entanglement entropy ...

Probing the two-scale-factor universality hypothesis by exact rotation symmetry-breaking mechanism

We probe the two-scale-factor universality hypothesis by evaluating, firstly explicitly and analytically at the one-loop order, the loop quantum corrections to the amplitude ratios for O(N) \(\lambda \phi ^{4}\) scalar field theories with rotation symmetry breaking in three distinct and independent methods in which the rotation symmetry-breaking mechanism is treated exactly. We ...

Electroweak Higgs production with HiggsPO at NLO QCD

We present the HiggsPO UFO model for Monte Carlo event generation of electroweak VH and VBF Higgs production processes at NLO in QCD in the formalism of Higgs pseudo-observables (PO). We illustrate the use of this tool by studying the QCD corrections, matched to a parton shower, for several benchmark points in the Higgs PO parameter space. We find that, while being sizable and thus ...

Very heavy dark Skyrmions

A dark sector with a solitonic component provides a means to circumvent the problem of generically low annihilation cross sections of very heavy dark matter particles. At the same time, enhanced annihilation cross sections are necessary for indirect detection of very heavy dark matter components beyond 100 TeV. Non-thermally produced dark matter in this mass range could therefore ...

Interacting dark energy model and thermal stability

In the background of the homogeneous and isotropic FLRW model, the thermodynamics of the interacting DE fluid is investigated in the present work. By studying the thermodynamical parameters, namely the heat capacities and the compressibilities, both thermal and mechanical stability are discussed and the restrictions on the equation of state parameter of the dark fluid are analyzed.

Electron–positron annihilation into hadrons at the higher-loop levels

The strong corrections to the R-ratio of electron–positron annihilation into hadrons are studied at the higher-loop levels. Specifically, the derivation of a general form of the commonly employed approximate expression for the R-ratio (which constitutes its truncated re-expansion at high energies) is delineated, the appearance of the pertinent \(\pi ^2\)-terms is expounded, and ...

Search for dark matter produced in association with heavy-flavor quark pairs in proton-proton collisions at \(\sqrt{s}= 13\,\text{TeV} \)

A search is presented for an excess of events with heavy-flavor quark pairs (\({t}\overline{{t}} \) and \({b} \overline{{b}} \)) and a large imbalance in transverse momentum in data from proton–proton collisions at a center-of-mass energy of 13\(\,\text{TeV}\). The data correspond to an integrated luminosity of 2.2\(\,\text{fb}^{-1}\) collected with the CMS detector at the CERN ...

Reevaluation of the hadronic vacuum polarisation contributions to the Standard Model predictions of the muon \(g-2\) and \({\alpha (m_Z^2)}\) using newest hadronic cross-section data

We reevaluate the hadronic vacuum polarisation contributions to the muon magnetic anomaly and to the running of the electromagnetic coupling constant at the Z-boson mass. We include newest \(e^+e^- \rightarrow \mathrm{hadrons}\) cross-section data (among others) from the BABAR and VEPP-2000 experiments. For the muon \((g-2)/2\) we find for the lowest-order hadronic contribution ...

Electromagnetic dipole moments of charged baryons with bent crystals at the LHC

We propose a unique program of measurements of electric and magnetic dipole moments of charm, beauty and strange charged baryons at the LHC, based on the phenomenon of spin precession of channeled particles in bent crystals. Studies of crystal channeling and spin precession of positively- and negatively-charged particles are presented, along with feasibility studies and expected ...

Precise predictions for \(V+\) jets dark matter backgrounds

High-energy jets recoiling against missing transverse energy (MET) are powerful probes of dark matter at the LHC. Searches based on large MET signatures require a precise control of the \(Z(\nu {\bar{\nu }})+\) jet background in the signal region. This can be achieved by taking accurate data in control regions dominated by \(Z(\ell ^+\ell ^-)+\) jet, \(W(\ell \nu )+\) jet and ...

Families of vector-like deformations of relativistic quantum phase spaces, twists and symmetries

Families of vector-like deformed relativistic quantum phase spaces and corresponding realizations are analyzed. A method for a general construction of the star product is presented. The corresponding twist, expressed in terms of phase space coordinates, in the Hopf algebroid sense is presented. General linear realizations are considered and corresponding twists, in terms of momenta ...

DarkBit: a GAMBIT module for computing dark matter observables and likelihoods

We introduce DarkBit, an advanced software code for computing dark matter constraints on various extensions to the Standard Model of particle physics, comprising both new native code and interfaces to external packages. This release includes a dedicated signal yield calculator for gamma-ray observations, which significantly extends current tools by implementing a cascade-decay ...

Two Ramond–Ramond corrections to type II supergravity via field-theory amplitude

Motivated by the standard form of the string-theory amplitude, we calculate the field-theory amplitude to complete the higher-derivative terms in type II supergravity theories in their conventional form. We derive explicitly the \( O(\alpha '^3) \) interactions for the RR (Ramond–Ramond) fields with graviton, B-field and dilaton in the low-energy effective action of type II ...

Comments on gravitoelectromagnetism of Ummarino and Gallerati in “Superconductor in a weak static gravitational field” vs other versions

Recently reported [Eur. Phys. J. C., 77, 549 (2017). https://​doi.​org/​10.​1140/​epjc/​s10052-017-5116-y] gravitoelectromagnetic equations of Ummarino and Gallerati (UG) in their linearized version of general relativity (GR) are shown to match with (a) our previously reported special relativistic Maxwellian Gravity equations in the non-relativistic limit and with (b) the ...

Global fits of GUT-scale SUSY models with GAMBIT

We present the most comprehensive global fits to date of three supersymmetric models motivated by grand unification: the constrained minimal supersymmetric standard model (CMSSM), and its Non-Universal Higgs Mass generalisations NUHM1 and NUHM2. We include likelihoods from a number of direct and indirect dark matter searches, a large collection of electroweak precision and flavour ...

McVittie solution in f(T) gravity

We show that McVittie geometry, which describes a black hole embedded in a FLRW universe, not only solves the Einstein equations but also remains as a non-deformable solution of f(T) gravity. This search for GR solutions that survive in f(T) gravity is facilitated by a null tetrad approach. We also show that flat FLRW geometry is a consistent solution of f(T) dynamical equations ...

Some aspects of reconstruction using a scalar field in f(T) gravity

General relativity characterizes gravity as a geometric property exhibited on spacetime by massive objects, while teleparallel gravity achieves the same results at the level of equations, by taking a torsional perspective of gravity. Similar to the f(R) theory teleparallel gravity can also be generalized to f(T), with the resulting field equations being inherently distinct from ...

Bouncing solutions from generalized EoS

We present an exact analytical bouncing solution for a closed universe filled with only one exotic fluid with negative pressure, obeying a generalized equation of state (GEoS) of the form \(p(\rho )=A\rho +B\rho ^{\lambda }\), where A, B and \(\lambda \) are constants. In our solution \(A=-1/3\), \(\lambda =1/2\), and \(B<0\) is kept as a free parameter. For particular values of ...

Generating a resonance-like structure in the reaction \(B_c\rightarrow B_s \pi \pi \)

We investigate the process \(B_c^+\rightarrow B_s^0\pi ^+\pi ^0\) via \(B\bar{K}^*\) rescattering. The kinematic conditions for triangle singularities are perfectly satisfied in the rescattering diagrams. A resonance-like structure around the \(B\bar{K}\) threshold, which we denote X(5777), is predicted to be present in the invariant mass distribution of \(B_s^0 \pi ^+\). Because ...