Showing papers in "European Physical Journal C in 2018"

The waning of the WIMP? A review of models, searches, and constraints

Abstract: Weakly Interacting Massive Particles (WIMPs) are among the best-motivated dark matter candidates. No conclusive signal, despite an extensive search program that combines, often in a complementary way, direct, indirect, and collider probes, has been detected so far. This situation might change in near future due to the advent of one/multi-TON Direct Detection experiments. We thus, find it timely to provide a review of the WIMP paradigm with focus on a few models which can be probed at best by these facilities. Collider and Indirect Detection, nevertheless, will not be neglected when they represent a complementary probe.

Update of the global electroweak fit and constraints on two-Higgs-doublet models

Abstract: We present an update of the global fit of the Standard Model electroweak sector to latest experimental results. We include new kinematic top quark and W boson mass measurements from the LHC, a $$\sin \!^2\theta ^{\ell }_{\mathrm{eff}}$$ result from the Tevatron, and a new evaluation of the hadronic contribution to $$\alpha (M_Z^2)$$ . We present tests of the internal consistency of the electroweak Standard Model and updated numerical predictions of key observables. The electroweak data combined with measurements of the Higgs boson coupling strengths and flavour physics observables are used to constrain parameters of two-Higgs-doublet models.

The design of the MEG II experiment

Abstract: The MEG experiment, designed to search for the $${\mu ^+ \rightarrow \hbox {e}^+ \gamma }$$ decay, completed data-taking in 2013 reaching a sensitivity level of $${5.3\times 10^{-13}}$$ for the branching ratio. In order to increase the sensitivity reach of the experiment by an order of magnitude to the level of $$6\times 10^{-14}$$ , a total upgrade, involving substantial changes to the experiment, has been undertaken, known as MEG II. We present both the motivation for the upgrade and a detailed overview of the design of the experiment and of the expected detector performance.

Performance of missing transverse momentum reconstruction with the ATLAS detector using proton-proton collisions at s√ = 13 TeV

Abstract: The performance of the missing transverse momentum ( ETmiss ) reconstruction with the ATLAS detector is evaluated using data collected in proton-proton collisions at the LHC at a centre-of-mass energy of 13 TeV in 2015. To reconstruct ETmiss , fully calibrated electrons, muons, photons, hadronically decaying τ-leptons , and jets reconstructed from calorimeter energy deposits and charged-particle tracks are used. These are combined with the soft hadronic activity measured by reconstructed charged-particle tracks not associated with the hard objects. Possible double counting of contributions from reconstructed charged-particle tracks from the inner detector, energy deposits in the calorimeter, and reconstructed muons from the muon spectrometer is avoided by applying a signal ambiguity resolution procedure which rejects already used signals when combining the various ETmiss contributions. The individual terms as well as the overall reconstructed ETmiss are evaluated with various performance metrics for scale (linearity), resolution, and sensitivity to the data-taking conditions. The method developed to determine the systematic uncertainties of the ETmiss scale and resolution is discussed. Results are shown based on the full 2015 data sample corresponding to an integrated luminosity of 3.2fb-1 .

Anisotropic solutions by gravitational decoupling

Abstract: We investigate the extension of isotropic interior solutions for static self-gravitating systems to include the effects of anisotropic spherically symmetric gravitational sources by means of the gravitational decoupling realised via the minimal geometric deformation approach. In particular, the matching conditions at the surface of the star with the outer Schwarzschild space-time are studied in great detail, and we describe how to generate, from a single physically acceptable isotropic solution, new families of anisotropic solutions whose physical acceptability is also inherited from their isotropic parent.

Measurement of the W-boson mass in pp collisions at s=7TeV with the ATLAS detector.

Abstract: A measurement of the mass of the $W$ boson is presented based on proton-proton collision data recorded in 2011 at a centre-of-mass energy of 7 TeV with the ATLAS detector at the LHC, and corresponding to 4.6 fb$^{-1}$ of integrated luminosity. The selected data sample consists of $7.8 \times 10^6$ candidates in the $W\rightarrow \mu u$ channel and $5.9 \times 10^6$ candidates in the $W\rightarrow e u$ channel. The $W$-boson mass is obtained from template fits to the reconstructed distributions of the charged lepton transverse momentum and of the $W$ boson transverse mass in the electron and muon decay channels, yielding \begin{eqnarray} m_W &=& 80370 \pm 7 \, (\textrm{stat.}) \pm 11 \, (\textrm{exp. syst.}) \pm 14 \, (\textrm{mod. syst.}) \, \textrm{MeV} &=& 80370 \pm 19 \, \textrm{MeV}, \end{eqnarray} where the first uncertainty is statistical, the second corresponds to the experimental systematic uncertainty, and the third to the physics-modelling systematic uncertainty. A measurement of the mass difference between the $W^+$ and $W^-$ bosons yields $m_{W^+}-m_{W^-} = -29 \pm 28$ MeV.

Search for electroweak production of supersymmetric particles in final states with two or three leptons at √s=13 TeV with the ATLAS detector

Abstract: A search for the electroweak production of charginos, neutralinos and sleptons decaying into final states involving two or three electrons or muons is presented. The analysis is based on 36.1 fb$^{-1}$ of $\sqrt{s}=13$ TeV proton–proton collisions recorded by the ATLAS detector at the Large Hadron Collider. Several scenarios based on simplified models are considered. These include the associated production of the next-to-lightest neutralino and the lightest chargino, followed by their decays into final states with leptons and the lightest neutralino via either sleptons or Standard Model gauge bosons, direct production of chargino pairs, which in turn decay into leptons and the lightest neutralino via intermediate sleptons, and slepton pair production, where each slepton decays directly into the lightest neutralino and a lepton. No significant deviations from the Standard Model expectation are observed and stringent limits at 95% confidence level are placed on the masses of relevant supersymmetric particles in each of these scenarios. For a massless lightest neutralino, masses up to 580 GeV are excluded for the associated production of the next-to-lightest neutralino and the lightest chargino, assuming gauge-boson mediated decays, whereas for slepton-pair production masses up to 500 GeV are excluded assuming three generations of mass-degenerate sleptons.

Fully differential NNLO computations with MATRIX

Abstract: We present the computational framework Matrix ( http://matrix.hepforge.org/ ) which allows us to evaluate fully differential cross sections for a wide class of processes at hadron colliders in next-to-next-to-leading order (NNLO) QCD. The processes we consider are $$2\rightarrow 1$$ and $$2\rightarrow 2$$ hadronic reactions involving Higgs and vector bosons in the final state. All possible leptonic decay channels of the vector bosons are included for the first time in the calculations, by consistently accounting for all resonant and non-resonant diagrams, off-shell effects and spin correlations. We briefly introduce the theoretical framework Matrix is based on, discuss its relevant features and provide a detailed description of how to use Matrix to obtain NNLO accurate results for the various processes. We report reference predictions for inclusive and fiducial cross sections of all the physics processes considered here and discuss their corresponding uncertainties. Matrix features an automatic extrapolation procedure that allows us, for the first time, to control the systematic uncertainties inherent to the applied NNLO subtraction procedure down to the few permille level (or better).

Search for doubly charged Higgs boson production in multi-lepton final states with the ATLAS detector using proton-proton collisions at s=13TeV.

Abstract: A search for doubly charged Higgs bosons with pairs of prompt, isolated, highly energetic leptons with the same electric charge is presented. The search uses a proton–proton collision data sample at a centre-of-mass energy of 13 TeV corresponding to 36.1 $$\text {fb}^{-1}$$ of integrated luminosity recorded in 2015 and 2016 by the ATLAS detector at the LHC. This analysis focuses on the decays $$H^{\pm \pm }\rightarrow e^{\pm }e^{\pm }$$ , $$H^{\pm \pm }\rightarrow e^{\pm }\mu ^{\pm }$$ and $$H^{\pm \pm }\rightarrow \mu ^{\pm }\mu ^{\pm }$$ , fitting the dilepton mass spectra in several exclusive signal regions. No significant evidence of a signal is observed and corresponding limits on the production cross-section and consequently a lower limit on $$m(H^{\pm \pm })$$ are derived at 95% confidence level. With $$\ell ^{\pm }\ell ^{\pm }=e^{\pm }e^{\pm }/\mu ^{\pm }\mu ^{\pm }/e^{\pm }\mu ^{\pm }$$ , the observed lower limit on the mass of a doubly charged Higgs boson only coupling to left-handed leptons varies from 770 to 870 GeV (850 GeV expected) for $$B(H^{\pm \pm }\rightarrow \ell ^{\pm }\ell ^{\pm })=100\%$$ and both the expected and observed mass limits are above 450 GeV for $$B(H^{\pm \pm }\rightarrow \ell ^{\pm }\ell ^{\pm })=10\%$$ and any combination of partial branching ratios.

Status of the Charged Higgs Boson in Two Higgs Doublet Models

Abstract: The existence of charged Higgs boson(s) is inevitable in models with two (or more) Higgs doublets. Hence, their discovery would constitute unambiguous evidence for new physics beyond the Standard Model (SM). Taking into account all relevant results from direct charged and neutral Higgs boson searches at LEP and the LHC, as well as the most recent constraints from flavour physics, we present a detailed analysis of the current phenomenological status of the charged Higgs sector in a variety of well-motivated two Higgs doublet models (2HDMs). We find that charged Higgs bosons as light as $$75~\mathrm {GeV}$$ can still be compatible with the combined data, although this implies severely suppressed charged Higgs couplings to all fermions. In more popular models, e.g. the 2HDM of Type II, we find that flavour physics observables impose a combined lower limit on the charged Higgs mass of $$M_{H^\pm } \gtrsim 600$$ GeV – independent of $$\tan \beta $$ – which increases to $$M_{H^\pm } \gtrsim 650$$ GeV for $$\tan \beta < 1$$ . We furthermore find that in certain scenarios, the signature of a charged Higgs boson decaying into a lighter neutral Higgs boson and a W boson provides a promising experimental avenue that would greatly complement the existing LHC search programme for charged Higgs boson(s).

Reconciling EFT and hybrid calculations of the light MSSM Higgs-boson mass

Abstract: Various methods are used in the literature for predicting the lightest CP-even Higgs boson mass in the Minimal Supersymmetric Standard Model (MSSM). Fixed-order diagrammatic calculations capture all effects at a given order and yield accurate results for scales of supersymmetric (SUSY) particles that are not separated too much from the weak scale. Effective field theory calculations allow a resummation of large logarithmic contributions up to all orders and therefore yield accurate results for a high SUSY scale. A hybrid approach, where both methods have been combined, is implemented in the computer code FeynHiggs. So far, however, at large scales sizeable differences have been observed between FeynHiggs and other pure EFT codes. In this work, the various approaches are analytically compared with each other in a simple scenario in which all SUSY mass scales are chosen to be equal to each other. Three main sources are identified that account for the major part of the observed differences. Firstly, it is shown that the scheme conversion of the input parameters that is commonly used for the comparison of fixed-order results is not adequate for the comparison of results containing a series of higher-order logarithms. Secondly, the treatment of higher-order terms arising from the determination of the Higgs propagator pole is addressed. Thirdly, the effect of different parametrizations in particular of the top Yukawa coupling in the non-logarithmic terms is investigated. Taking into account all of these effects, in the considered simple scenario very good agreement is found for scales above 1 TeV between the results obtained using the EFT approach and the hybrid approach of FeynHiggs.

The Weak Gravity Conjecture and Emergence from an Ultraviolet Cutoff

Abstract: We study ultraviolet cutoffs associated with the Weak Gravity Conjecture (WGC) and Sublattice Weak Gravity Conjecture (sLWGC). There is a magnetic WGC cutoff at the energy scale $$e G_N^{-1/2}$$ with an associated sLWGC tower of charged particles. A more fundamental cutoff is the scale at which gravity becomes strong and field theory breaks down entirely. By clarifying the nature of the sLWGC for nonabelian gauge groups we derive a parametric upper bound on this strong gravity scale for arbitrary gauge theories. Intriguingly, we show that in theories approximately saturating the sLWGC, the scales at which loop corrections from the tower of charged particles to the gauge boson and graviton propagators become important are parametrically identical. This suggests a picture in which gauge fields emerge from the quantum gravity scale by integrating out a tower of charged matter fields. We derive a converse statement: if a gauge theory becomes strongly coupled at or below the quantum gravity scale, the WGC follows. We sketch some phenomenological consequences of the UV cutoffs we derive.

Black holes by gravitational decoupling

Abstract: We investigate how a spherically symmetric fluid modifies the Schwarzschild vacuum solution when there is no exchange of energy-momentum between the fluid and the central source of the Schwarzschild metric. This system is described by means of the gravitational decoupling realised via the minimal geometric deformation approach, which allows us to prove that the fluid must be anisotropic. Several cases are then explicitly shown.

Parton distributions with small-x resummation: evidence for BFKL dynamics in HERA data

Abstract: We present a determination of the parton distribution functions of the proton in which NLO and NNLO fixed-order calculations are supplemented by NLLx small-x resummation. Deep-inelastic structure functions are computed consistently at $$\hbox {NLO+NLL}x$$ or $$\hbox {NNLO+NLL}x$$ , while for hadronic processes small-x resummation is included only in the PDF evolution, with kinematic cuts introduced to ensure the fitted data lie in a region where the fixed-order calculation of the hard cross-sections is reliable. In all other respects, the fits use the same methodology and are based on the same global dataset as the recent NNPDF3.1 analysis. We demonstrate that the inclusion of small-x resummation leads to a quantitative improvement in the perturbative description of the HERA inclusive and charm-production reduced cross-sections in the small x region. The impact of the resummation in our fits is greater at NNLO than at NLO, because fixed-order calculations have a perturbative instability at small x due to large logarithms that can be cured by resummation. We explore the phenomenological implications of PDF sets with small-x resummation for the longitudinal structure function $$F_L$$ at HERA, for parton luminosities and LHC benchmark cross-sections, for ultra-high-energy neutrino–nucleus cross-sections, and for future high-energy lepton–proton colliders such as the LHeC.

Thermodynamic approach to holographic dark energy and the Rényi entropy

Abstract: Using the first law of thermodynamics, we propose a relation between the system entropy (S) and its IR (L) and UV ( $$\Lambda $$ ) cutoffs. In addition, applying this relation to the apparent horizon of flat FRW universe, whose entropy meets the Renyi entropy, a new holographic dark energy model is addressed. Thereinafter, the evolution of the flat FRW universe, filled by a pressureless source and the obtained dark energy candidate, is studied. In our model, there is no mutual interaction between the cosmos sectors. We find out that the obtained model is theoretically powerful to explain the current accelerated phase of the universe. This result emphasizes that the generalized entropy formalism is suitable for describing systems including the long-range interactions such as gravity.

Analysis of vector boson production within TMD factorization

Abstract: We present a comprehensive analysis and extraction of the unpolarized transverse momentum dependent (TMD) parton distribution functions, which are fundamental constituents of the TMD factorization theorem. We provide a general review of the theory of TMD distributions, and present a new scheme of scale fixation. This scheme, called the zeta-prescription, allows to minimize the impact of perturbative logarithms in a large range of scales and does not generate undesired power corrections. Within zeta-prescription we consistently include the perturbatively calculable parts up to next-to-next-to-leading order (NNLO), and perform the global fit of the Drell-Yan and Z-boson production, which include the data of E288, Tevatron and LHC experiments. The non-perturbative part of the TMDs are explored checking a variety of models. We support the obtained results by a study of theoretical uncertainties, perturbative convergence, and a dedicated study of the range of applicability of the TMD factorization theorem. The considered non-perturbative models present significant differences in the fitting behavior, which allow us to clearly disfavor most of them. The numerical evaluations are provided by the arTeMiDe code, which is introduced in this work and that can be used for current/future TMD phenomenology.

B -decay anomalies in Pati–Salam SU(4)

Abstract: Attempts to incorporate in a coherent picture the B-decay anomalies presumably observed in $$b\rightarrow c$$ and $$b\rightarrow s$$ semi-leptonic decays have to face the absence of signals in other related experiments, both at low and at high energies. By extending and making more precise the content of Barbieri et al. (Eur Phys J C 77(1):8, 2017), we describe one such attempt based on the Pati–Salam SU(4) group, that unifies colour and the B-L charge, in the context of a new strongly interacting sector, equally responsible for producing a pseudo-Goldstone Higgs boson.

Spectroscopy and decays of the fully-heavy tetraquarks

Abstract: We discuss the possible existence of the fully-heavy tetraquarks. We calculate the ground-state energy of the $$bb {\bar{b}} {\bar{b}}$$ bound state, where b stands for the bottom quark, in a nonrelativistic effective field theory framework with one-gluon-exchange (OGE) color Coulomb interaction, and in a relativized diquark model characterized by OGE plus a confining potential. Our analysis advocates the existence of uni-flavor heavy four-quark bound states. The ground state $$bb{\bar{b}}{\bar{b}}$$ tetraquark mass is predicted to be $$(18.72\pm 0.02)$$ GeV. Mass inequality relations among the lowest $$QQ\bar{Q}\bar{Q}$$ states, where $$Q\in \{c, b\}$$ , and the corresponding heavy quarkonia are presented, which give the upper limit on the mass of ground state $$QQ\bar{Q}\bar{Q}$$ . The possible decays of the lowest $$bb\bar{b}\bar{b}$$ are highlighted, which might provide useful references in the search for them in ongoing LHC experiments, and its width is estimated to be a few tens of MeV.

a Python package for the running and matching of Wilson coefficients above and below the electroweak scale

Abstract: wilson is a Python library for matching and running Wilson coefficients of higher-dimensional operators beyond the Standard Model. Provided with the numerical values of the Wilson coefficients at a high new physics scale, it automatically performs the renormalization group evolution within the Standard Model effective field theory (SMEFT), matching onto the weak effective theory (WET) at the electroweak scale, and QCD/QED renormalization group evolution below the electroweak scale down to hadronic scales relevant for low-energy precision tests. The matching and running encompasses the complete set of dimension-six operators in both SMEFT and WET. The program builds on the Wilson coefficient exchange format (WCxf) and can thus be easily combined with a number of existing public codes.

Charmed hadrons from coalescence plus fragmentation in relativistic nucleus-nucleus collisions at RHIC and LHC

Abstract: In a coalescence plus fragmentation approach we calculate the heavy baryon/meson ratio and the $$p_T$$ spectra of charmed hadrons $$D^{0}$$ , $$D_{s}$$ and $$\varLambda _{c}^{+}$$ in a wide range of transverse momentum from low $$p_T$$ up to about 10 GeV and discuss their ratios from RHIC to LHC energies without any change of the coalescence parameters. We have included the contribution from decays of heavy hadron resonances and also the one due to fragmentation of heavy quarks which do not undergo the coalescence process. The coalescence process is tuned to have all charm quarks hadronizing in the $$p_T\rightarrow 0$$ limit and at finite $$p_T$$ charm quarks not undergoing coalescence are hadronized by independent fragmentation. The $$p_T$$ dependence of the baryon/meson ratios are found to be sensitive to the masses of coalescing quarks, in particular the $$\varLambda _{c}/D^{0}$$ can reach values of about $$\mathrm 1\div 1.5 $$ at $$p_T \approx \, 3$$ GeV, or larger, similarly to the light baryon/meson ratio like $$p/\pi $$ and $$\varLambda /K$$ , however a marked difference is a quite weak $$p_T$$ dependence with respect to the light case, such that a larger value at intermediate $$p_T$$ implies a relatively large value also for the integrated yields. A comparison with other coalescence model and with the prediction of thermal model is discussed.

Light escape cones in local reference frames of Kerr–de Sitter black hole spacetimes and related black hole shadows

Abstract: We construct the light escape cones of isotropic spot sources of radiation residing in special classes of reference frames in the Kerr–de Sitter (KdS) black hole spacetimes, namely in the fundamental class of ‘non-geodesic’ locally non-rotating reference frames (LNRFs), and two classes of ‘geodesic’ frames, the radial geodesic frames (RGFs), both falling and escaping, and the frames related to the circular geodesic orbits (CGFs). We compare the cones constructed in a given position for the LNRFs, RGFs, and CGFs. We have shown that the photons locally counter-rotating relative to LNRFs with positive impact parameter and negative covariant energy are confined to the ergosphere region. Finally, we demonstrate that the light escaping cones govern the shadows of black holes located in front of a radiating screen, as seen by the observers in the considered frames. For shadows related to distant static observers the LNRFs are relevant.

Discrete Flavour Symmetries, Neutrino Mixing and Leptonic CP Violation

Abstract: The current status of our knowledge of the 3-neutrino mixing parameters and of the CP violation in the lepton sector is summarised. The non-Abelian discrete symmetry approach to understanding the observed pattern of neutrino mixing and the related predictions for neutrino mixing angles and leptonic Dirac CP violation are reviewed. Possible tests of these predictions using the existing data on neutrino mixing angles as well as prospective data from current and future neutrino oscillation experiments (T2K, NO $$ u $$ A, Daya Bay, T2HK, T2HKK, DUNE) are also discussed.

Thermal Resummation and Phase Transitions

Abstract: The consequences of phase transitions in the early universe are becoming testable in a variety of manners, from colliders physics to gravitational wave astronomy. In particular one phase transition we know of, the electroweak phase transition (EWPT), could potentially be first order in BSM scenarios and testable in the near future. If confirmed this could provide a mechanism for baryogenesis, which is one of the most important outstanding questions in physics. To reliably make predictions it is necessary to have full control of the finite temperature scalar potentials. However, as we show the standard methods used in BSM physics to improve phase transition calculations, resumming hard thermal loops, introduces significant errors into the scalar potential. In addition, the standard methods make it impossible to match theories to an EFT description reliably. In this paper we define a thermal resummation procedure based on partial dressing (PD) for general BSM calculations of phase transitions beyond the high-temperature approximation. Additionally, we introduce the modified optimized partial dressing (OPD) procedure, which is numerically nearly as efficient as old incorrect methods, while yielding identical results to the full PD calculation. This can be easily applied to future BSM studies of phase transitions in the early universe. As an example, we show that in unmixed singlet scalar extensions of the SM, the (O)PD calculations make new phenomenological predictions compared to previous analyses. An important future application is the study of EFTs at finite temperature.

Towards apparent convergence in asymptotically safe quantum gravity

Abstract: The asymptotic safety scenario in gravity is accessed within the systematic vertex expansion scheme for functional renormalisation group flows put forward in Christiansen et al. (Phys Lett B 728:114, 2014), Christiansen et al. (Phy Rev D 93:044036, 2016), and implemented in Christiansen et al. (Phys Rev D 92:121501, 2015) for propagators and three-point functions. In the present work this expansion scheme is extended to the dynamical graviton four-point function. For the first time, this provides us with a closed flow equation for the graviton propagator: all vertices and propagators involved are computed from their own flows. In terms of a covariant operator expansion the current approximation gives access to $$\Lambda $$ , R, $$R^2$$ as well as $$R_{\mu u }^2$$ and higher derivative operators. We find a UV fixed point with three attractive and two repulsive directions, thus confirming previous studies on the relevance of the first three operators. In the infrared we find trajectories that correspond to classical general relativity and further show non-classical behaviour in some fluctuation couplings. We also find signatures for the apparent convergence of the systematic vertex expansion. This opens a promising path towards establishing asymptotically safe gravity in terms of apparent convergence.

Gravitational decoupled anisotropies in compact stars

Abstract: Simple generic extensions of isotropic Durgapal–Fuloria stars to the anisotropic domain are presented. These anisotropic solutions are obtained by guided minimal deformations over the isotropic system. When the anisotropic sector interacts in a purely gravitational manner, the conditions to decouple both sectors by means of the minimal geometric deformation approach are satisfied. Hence the anisotropic field equations are isolated resulting a more treatable set. The simplicity of the equations allows one to manipulate the anisotropies that can be implemented in a systematic way to obtain different realistic models for anisotropic configurations. Later on, observational effects of such anisotropies when measuring the surface redshift are discussed. To conclude, the consistency of the application of the method over the obtained anisotropic configurations is shown. In this manner, different anisotropic sectors can be isolated of each other and modeled in a simple and systematic way.

Gravitational decoupled charged anisotropic spherical solutions

Abstract: The purpose of this paper is to obtain exact solutions for charged anisotropic spherically symmetric matter configuration. For this purpose, we consider known solution for isotropic spherical system in the presence of electromagnetic field and extend it to two types of anisotropic charged solutions through gravitational decoupling approach. We examine physical characteristics of the resulting models. It is found that only first solution is physically acceptable as it meets all the energy bounds as well as stability criterion. We conclude that stability of the first model is enhanced with the increase of charge.

Minimal geometric deformation in a cloud of strings

Abstract: We find new exact analytical solutions in three-dimensional gravity applying the Minimal Geometric Deformation approach in a cloud of strings.

Relativistic quantum motion of spin-0 particles under the influence of noninertial effects in the cosmic string spacetime

Abstract: We study solutions for the Klein–Gordon equation with vector and scalar potentials of the Coulomb types under the influence of noninertial effects in the cosmic string spacetime. We also investigate a quantum particle described by the Klein–Gordon oscillator in the background spacetime generated by a cosmic string. An important result obtained is that the noninertial effects restrict the physical region of the spacetime where the particle can be placed. In addition, we show that these potentials can form bound states for the Klein–Gordon equation in this kind of background.

Long-distance effects in $$B\rightarrow K^*\ell \ell $$ B → K ∗ ℓ ℓ from analyticity

Abstract: We discuss a novel approach to systematically determine the dominant long-distance contribution to $$B\rightarrow K^*\ell \ell $$ decays in the kinematic region where the dilepton invariant mass is below the open charm threshold. This approach provides the most consistent and reliable determination to date and can be used to compute Standard Model predictions for all observables of interest, including the kinematic region where the dilepton invariant mass lies between the $$J/\psi $$ and the $$\psi (2S)$$ resonances. We illustrate the power of our results by performing a New Physics fit to the Wilson coefficient $$C_9$$ . This approach is systematically improvable from theoretical and experimental sides, and applies to other decay modes of the type $$B\rightarrow V\ell \ell $$ , $$B\rightarrow P\ell \ell $$ and $$B\rightarrow V\gamma $$ .

Agravity up to infinite energy

Abstract: The self-interactions of the conformal mode of the graviton are controlled, in dimensionless gravity theories (agravity), by a coupling $$f_0$$ that is not asymptotically free. We show that, nevertheless, agravity can be a complete theory valid up to infinite energy. When $$f_0$$ grows to large values, the conformal mode of the graviton decouples from the rest of the theory and does not hit any Landau pole provided that scalars are asymptotically conformally coupled and all other couplings approach fixed points. Then agravity can flow to conformal gravity at infinite energy. We identify scenarios where the Higgs mass does not receive unnaturally large physical corrections. We also show a useful equivalence between agravity and conformal gravity plus two extra conformally coupled scalars, and we give a simpler form for the renormalization group equations of dimensionless couplings as well as of massive parameters in the presence of the most general matter sector.