The European Physical Journal C

List of Papers (Total 3,659)

The impact of LHC jet data on the MMHT PDF fit at NNLO

We investigate the impact of the high precision ATLAS and CMS 7 TeV measurements of inclusive jet production on the MMHT global PDF analysis at next-to-next-to-leading order (NNLO). This is made possible by the recent completion of the long-term project to calculate the NNLO corrections to the hard cross section. We find that a good description of the ATLAS data is not possible...

Simple cosmological model with inflation and late times acceleration

In the framework of polynomial Palatini cosmology, we investigate a simple cosmological homogeneous and isotropic model with matter in the Einstein frame. We show that in this model during cosmic evolution, early inflation appears and the accelerating phase of the expansion for the late times. In this frame we obtain the Friedmann equation with matter and dark energy in the form...

Uncovering novel phase structures in $$\Box ^k$$ scalar theories with the renormalization group

We present a detailed version of our recent work on the RG approach to multicritical scalar theories with higher derivative kinetic term $$\phi (-\Box )^k\phi$$ and upper critical dimension $$d_c = 2nk/(n-1)$$. Depending on whether the numbers k and n have a common divisor two classes of theories have been distinguished. For coprime k and $$n-1$$ the theory admits a Wilson...

Pre-inflation from the multiverse: can it solve the quadrupole problem in the cosmic microwave background?

We analyze a quantized toy model of a universe undergoing eternal inflation using a quantum-field-theoretical formulation of the Wheeler–DeWitt equation. This so-called third quantization method leads to the picture that the eternally inflating universe is converted to a multiverse in which sub-universes are created and exhibit a distinctive phase in their evolution before...

Reconstructing warm inflation

The reconstruction of a warm inflationary universe model from the scalar spectral index $$n_S(N)$$ and the tensor to scalar ratio r(N) as a function of the number of e-folds N is studied. Under a general formalism we find the effective potential and the dissipative coefficient in terms of the cosmological parameters $$n_S$$ and r considering the weak and strong dissipative stages...

Compact stars in the non-minimally coupled electromagnetic fields to gravity

We investigate the gravitational models with the non-minimal $$Y(R)F^2$$ coupled electromagnetic fields to gravity, in order to describe charged compact stars, where Y(R) denotes a function of the Ricci curvature scalar R and $$F^2$$ denotes the Maxwell invariant term. We determine two parameter family of exact spherically symmetric static solutions and the corresponding non...

Running of the spectral index in deformed matter bounce scenarios with Hubble-rate-dependent dark energy

As a deformed matter bounce scenario with a dark energy component, we propose a deformed one with running vacuum model (RVM) in which the dark energy density $$\rho _{\Lambda }$$ is written as a power series of $$H^2$$ and $$\dot{H}$$ with a constant equation of state parameter, same as the cosmological constant, $$w=-1$$. Our results in analytical and numerical point of views...

Refractive index in generalized superconductors with Born–Infeld electrodynamics

We investigate, in the probe limit, the negative refraction in the generalized superconductors with the Born–Infeld electrodynamics. We observe that the system has a negative Depine–Lakhtakia index in the superconducting phase at small frequencies and the greater the Born–Infeld corrections the larger the range of frequencies or the range of temperatures for which the negative...

Merging NLO multi-jet calculations with improved unitarization

We present an algorithm to combine multiple matrix elements at LO and NLO with a parton shower. We build on the unitarized merging paradigm. The inclusion of higher orders and multiplicities reduce the scale uncertainties for observables sensitive to hard emissions, while preserving the features of inclusive quantities. The combination allows further soft and collinear emissions...

Anomaly-free models for flavour anomalies

We explore the constraints imposed by the cancellation of triangle anomalies on models in which the flavour anomalies reported by LHCb and other experiments are due to an extra U(1)$$^\prime$$ gauge boson Z$$^\prime$$. We assume universal and rational U(1)$$^\prime$$ charges for the first two generations of left-handed quarks and of right-handed up-type quarks but allow...

A precise determination of the top-quark pole mass

The Principle of Maximum Conformality (PMC) provides a systematic way to eliminate the renormalization scheme and renormalization scale uncertainties for high-energy processes. We have observed that by applying PMC scale setting, one obtains comprehensive and self-consistent pQCD predictions for the top-quark pair total cross section and the top-quark pair forward–backward...

Regge trajectories for heavy quarkonia from the quadratic form of the spinless Salpeter-type equation

In this paper, we present one new form of the Regge trajectories for heavy quarkonia which is obtained from the quadratic form of the spinless Salpeter-type equation (QSSE) by employing the Bohr-Sommerfeld quantization approach. The obtained Regge trajectories take the parameterized form $$M^2={\beta }({c_l}l+{\pi }n_r+c_0)^{2/3}+c_1$$, which are different from the present Regge...

The NNLO QCD soft function for 1-jettiness

We calculate the soft function for the global event variable 1-jettiness at next-to-next-to-leading order (NNLO) in QCD. We focus specifically on the non-Abelian contribution, which, unlike the Abelian part, is not determined by the next-to-leading order result. The calculation uses the known general forms for the emission of one and two soft partons and is performed using a...

Bouncing universe of entropy-corrected Friedmann equations

In this paper, we investigate the possibility of obtaining bouncing-oscillating solution in modified Friedmann equations with logarithmic entropy corrected, $$S=\frac{A}{4G}+\alpha \ln \frac{A}{4G}+\beta \frac{4G}{A}$$, for positive, negative and zero values of $$(\alpha ,\beta )$$ pre-factors and all kinds of curved universes. The results are argued using the dynamical system...

Status of quarkonia-like negative and positive parity states in a relativistic confinement scheme

Properties of quarkonia-like states in the charm and bottom sector have been studied in the frame work of relativistic Dirac formalism with a linear confinement potential. We have computed the mass spectroscopy and decay properties (vector decay constant and leptonic decay width) of several quarkonia-like states. The present study is also intended to identify some of the...

Fragmentation-fra ction ratio $$f_{\Xi _ b}/f_{\Lam bda _ b}$$fΞ b/fΛ b in b- and c- baryon de cays

We study the ratio of fragmentation fractions, $$f_{\Xi _b}/f_{\Lambda _b}$$, from the measurement of $$\Xi _b^0\rightarrow \Xi _c^+\pi ^-$$ and $$\Lambda _b^0\rightarrow \Lambda _c^+\pi ^-$$ with $$\Xi _{c}^{+}/\Lambda _{c}^{+}\rightarrow p K^-\pi ^+$$. With the branching fraction $$\mathcal {B}(\Xi _c^+\rightarrow pK^-\pi ^+)=(2.2\pm 0.8)\%$$ obtained under the U-spin symmetry...

Some dipole shower studies

Parton showers have become a standard component in the description of high-energy collisions. Nowadays most final-state ones are of the dipole character, wherein a pair of partons branches into three, with energy and momentum preserved inside this subsystem. For initial-state showers a dipole picture is also possible and commonly used, but the older global-recoil strategy remains...

Non-perturbative electroweak-scalegenesis on the test bench of dark matter detection

We revisit a recently proposed scale invariant extension of the standard model, in which the scalar bi-linear condensate in a strongly interacting hidden sector dynamically breaks scale symmetry, thereby triggering electroweak symmetry breaking. Relaxing the previously made assumption on $$U(N_f)$$ flavor symmetry we find that the presence of the would-be dark matter candidate...

Once more on Coulomb-nuclear interference

This is a critical reconsideration of the standard way of account for Coulomb-nuclear interference in the elastic scattering amplitude.

Torsion axial vector and Yvon-Takabayashi angle: zitterbewegung, chirality and all that

We consider propagating torsion as a completion of gravitation in order to describe the dynamics of curved-twisted space-times filled with Dirac spinorial fields; we discuss interesting relationships of the torsion axial vector and the curvature tensor with the Yvon-Takabayashi angle and the module of the spinor field, that is the two degrees of freedom of the spinor field itself...