Search

Infrared renormalons in Quantum Chromodynamics are associated with non-perturbative corrections to short distance observables. Linear renormalons, i.e. such that the associated non-perturbative corrections scale like one inverse power of the hard scale, can affect at a non-negligible level even the very high-energy phenomena studied at the Large Hadron Collider. Using an Abelian model, we study the presence of linear renormalons in the transverse momentum distribution of a neutral vector boson $Z$ produced in hadronic collisions. We consider a process where the $Z$ transverse momentum is balanced by a sizable recoil against a coloured final state particle. One may worry that such a colour configuration, not being azimuthally symmetric, could generate unbalanced soft radiation, associated in turn with linear infrared renormalons affecting the transverse momentum distribution of the vector boson. We performed a numerical calculation of the renormalon effects for this process in the so-called large $b_0$ limit. We found no evidence of linear renormalons in the transverse momentum distribution of the $Z$ in the large transverse-momentum region, irrespective of rapidity cuts., Comment: 24 pages, 10 figures

We have analysed the observable consequences of the interactions of spin-1 resonances coupled to the invariant fermionic currents that arise in an $SO(5)$ Composite Higgs set-up. The phenomenology entailed by such interactions is thoroughly analysed by studying heavy vector resonances production and decay modes in the viable resonance mass range. Additionally, the production of double and single-composite fermion final states has been scanned along the fermion mass scale. Such production is mediated by the SM gauge and Higgs interactions, and also by charged and neutral vector resonances. The coupling between the new fermions and vector resonances induces a sizeable effect in the production rates. We use the recent 13 TeV LHC searches for vector-like quarks to constrain our parameter space. Specifically, we explore the allowed regions by analysing the decays of a heavy vector-like quark in the $Wb$-channel. We conclude that generically the impact of the couplings between the spin-1 and spin-1/2 resonances will substantially reduce the permitted regions, leading us to test the sensitivity of the parametric dependence in the light of exotic matter interactions., Comment: 30 pages, 40 figures, references added and some sections shortened. arXiv admin note: text overlap with arXiv:1405.1617, arXiv:1211.5663 by other authors. References and footnotes added

This report presents possible loopholes in heavy Z′ searches which are concentrated around high-mass resonances. We present a scenario where massive neutral vector boson Z′, predicted by E6-inspired U(1)′ models, can become leptophobic due to kinetic mixing between Z − Z′. Such a scenario can avoid high-mass dilepton resonance searches. Furthermore, we propose a channel through supersymmetric cascade decays to observe leptophobic Z′. We show that it is possible to reach up to 8σ at \( \sqrt {s} = 14 \) TeV and 3 ab−1 integrated luminosity. This report follows the steps of the work that has been conducted in Araz et al. (J High Energy Phys 02:092, 2018).

We observed the impact of finite magnetic field on the in-medium mass and decay constant of isospin averaged vector $D^*(D^{*^+},D^{*^0})$ and axial-vector $D_1(D^+_1, D^0_1)$ mesons. The quark and gluon condensates of the nuclear medium at finite magnetic field, temperature, isospin asymmetry, and density have been obtained by the meson exchange scalar fields within the chiral SU(3) model. The medium attributes modify the scalar and vector density of nuclear medium and this variation reflects in the in-medium mass and decay constant of spin 1 $D$ mesons. We calculate these observables by comparing the Operator Product Expansion (OPE) and the phenomenological side in the QCD Sum Rules. In the results, we observed a positive mass shift for charged vector and axial-vector $D$ mesons with respect to magnetic field. For neutral vector (axial-vector) $D$ mesons we observed negative (positive) mass shift as a function of magnetic field. In the application part, we calculate the in-medium partial decay width of the process $D^*_s$(2715/2860) $\rightarrow$ $D^* K$ by using $^3P_0$ model. The in-medium effects are incorporated through the in-medium masses of $D^*$ and $K$ mesons., Comment: 36 Pages, 11 figures

Journal of high energy physics 10(10), 153 (1-45) (2020). doi:10.1007/JHEP10(2020)153, We present the resummed predictions for inclusive cross-section for Drell-Yan (DY) production as well as onshell Z, W$^{±}$ productions at next-to-next-to-next-to leading logarithmic (N$^{3}$LL) accuracy. Using the standard techniques, we derive the N-dependent coefficients in the Mellin-N space as well as the N-independent constants and match the resummed result through the minimal prescription procedure with the fixed order results. In addition to the standard ln N exponentiation, we study the numerical impacts of exponentiating N-independent part of the soft function and the complete $ {\overline{g}}_0 $ that appears in the resummed predictions in N space. All the analytical pieces needed in these different approaches are extracted from the soft-virtual part of the inclusive cross section known to next-to-next-to-next-to leading order (N$^{3}$LO). We perform a detailed analysis on the scale and parton distribution function (PDF) variations and present predictions for 13 TeV LHC for the neutral Drell-Yan process as well as onshell charged and neutral vector boson productions., Published by SISSA, [Trieste]

We investigate the rare electromagnetic decays of neutral vector mesons (exemplified by $J/\psi$, $\Upsilon$, $\rho^0$, $\omega,\phi$, \ldots) into four charged leptons ($2(e^+e^-)$, $2(\mu^+\mu^-)$, $2(\tau^+\tau^-)$, $e^+e^-\mu^+\mu^-$, $e^+e^-\tau^+\tau^-$, \ldots) at lowest order in QED. In contrast to the case of vector meson decay into a single pair of leptons, the lepton mass must be retained in these four-lepton decay channels to cutoff the mass singularity. Owing to more pronounced collinear enhancement, the branching fractions of vector mesons decays into $ 2(e^+e^-)$ are considerably greater than those for decays into $2(\mu^+\mu^-)$. The decay channels $J/\psi(\Upsilon)\to 2(e^+e^-), e^+e^-\mu^+\mu^-$ are predicted to have branching fractions of order $10^{-5}$, which appear to have bright observation prospect at {\tt BESIII}, {\tt Belle 2} and {\tt LHC} experiments., Comment: 10 pages, 6 figures, 4 tables

As a typical non-Gaussian vector variable, a neutral vector variable contains nonnegative elements only, and its l1 -norm equals one. In addition, its neutral properties make it significantly different from the commonly studied vector variables (e.g., the Gaussian vector variables). Due to the aforementioned properties, the conventionally applied linear transformation approaches [e.g., principal component analysis (PCA) and independent component analysis (ICA)] are not suitable for neutral vector variables, as PCA cannot transform a neutral vector variable, which is highly negatively correlated, into a set of mutually independent scalar variables and ICA cannot preserve the bounded property after transformation. In recent work, we proposed an efficient nonlinear transformation approach, i.e., the parallel nonlinear transformation (PNT), for decorrelating neutral vector variables. In this article, we extensively compare PNT with PCA and ICA through both theoretical analysis and experimental evaluations. The results of our investigations demonstrate the superiority of PNT for decorrelating the neutral vector variables.

Effects of Kaluza-Klein excited neutral vector bosons ($Z'$ bosons) in the gauge-Higgs unification on $e^+e^- \to \bar{q}q, \ell^+\ell^-$ cross sections are studied, particularly in future $e^+ e^-$ collider experiments with polarized beams. Significant deviations in the energy and polarization dependence in $\sigma(\mu^+\mu^-)$, the lepton forward-backward asymmetry, $R_b(\mu) \equiv \sigma(\bar{b}b)/\sigma(\mu^+\mu^-)$ and the left-right asymmetry from the standard model are predicted., Comment: 16 pages, 5 figures, 7 tables (v3) numerical evaluations renewed, comments and references added, 4 tables added

We obtain the pressures and equations of state (EoS) of charged and neutral vector boson gases in a constant magnetic field. The axial symmetry imposed to the system by the field splits the pressures in the parallel and perpendicular directions along the magnetic axis, and this leads to anisotropic equations of state. The values of pressures and energy densities are in the order of those of Fermi gases in compact objects. This opens the possibility to the existence of magnetized boson stars. Under certain conditions, the perpendicular pressure might be negative imposing a bound to the stability of the star. Other implications of negative pressures are also discussed.

We investigate a dimension five Lorentz-violating (LV) nonminimal coupling between the neutral vector meson field strength and the pion current in the context of the Kroll-Lee-Zumino (KLZ) model. In this modified model we study the vector meson dominance (VMD) through of the imposing of new universality conditions between the couplings that comes from LV contributions. We also show that the LV nonminimal coupling leads to a linear momentum dependence in the timelike pion form factor, that is used to evaluate LV corrections for the muon anomalous magnetic moment. The experimental imprecision of such quantity allows us to obtain upper bound $\bar{g}\xi_{0} < 1.0 \mathbf{~}\mathrm{{GeV}}^{-1}.$ In addition, we also use the LV nonminimal coupling in the KLZ model to recalculate the $\rho$ decay rate. In this case the experimental imprecision is used to constrain the magnitude of the LV parameter at the level of $\bar{g}\xi_{0} < 1.9\times10^{-2}\mathbf{~}\mathrm{{GeV}}^{-1}$., Comment: 8 pages, 2 figures, revtex4 style

We calculate the non-singlet, the pure singlet contribution, and their interference term, at $O(\alpha^2)$ due to electron-pair initial state radiation to $e^+ e^-$ annihilation into a neutral vector boson in a direct analytic computation without any approximation. The correction is represented in terms of iterated incomplete elliptic integrals. Performing the limit $s \gg m_e^2$ we find discrepancies with the earlier results of Ref.~\cite{Berends:1987ab} and confirm results obtained in Ref.~\cite{Blumlein:2011mi} where the effective method of massive operator matrix elements has been used, which works for all but the power corrections in $m^2/s$. In this way, we also confirm the validity of the factorization of massive partons in the Drell-Yan process. We also add non-logarithmic terms at $O(\alpha^2)$ which have not been considered in \cite{Berends:1987ab}. The corrections are of central importance for precision analyzes in $e^+e^-$ annihilation into $\gamma^*/Z^*$ at high luminosity., Comment: 4 pages Latex, 2 Figures, several style files

A linear response function (LRF) determines the mean response of a nonlinear climate system to weak imposed forcings, and an eddy flux matrix (EFM) determines the eddy momentum and heat flux responses to mean-flow changes. Neither LRF nor EFM can be calculated from first principles owing to the lack of a complete theory for turbulent eddies. Here the LRF and EFM for an idealized dry atmosphere are computed by applying numerous localized weak forcings, one at a time, to a GCM with Held–Suarez physics and calculating the mean responses. The LRF and EFM for zonally averaged responses are then constructed using these forcings and responses through matrix inversion. Tests demonstrate that LRF and EFM are fairly accurate. Spectral analysis of the LRF shows that the most excitable dynamical mode, the neutral vector, strongly resembles the model’s annular mode. The framework described here can be employed to compute the LRF and EFM for zonally asymmetric responses and more complex GCMs. The potential applications of the LRF and EFM constructed here are (i) forcing a specified mean flow for hypothesis testing, (ii) isolating/quantifying the eddy feedbacks in complex eddy–mean flow interaction problems, and (iii) evaluating/improving more generally applicable methods currently used to construct LRFs or diagnose eddy feedbacks in comprehensive GCMs or observations. As an example for (iii), in Part II, the LRF is also computed using the fluctuation–dissipation theorem (FDT), and the previously calculated LRF is exploited to investigate why FDT performs poorly in some cases. It is shown that dimension reduction using leading EOFs, which is commonly used to construct LRFs from the FDT, can significantly degrade the accuracy owing to the nonnormality of the operator.

We calculate the complete O ( α 2 ) initial state radiation corrections to e + e − annihilation into a neutral vector boson in a direct analytic computation without any approximation. The corrections are represented in terms of iterated incomplete (elliptic) integrals over alphabets of square-root valued letters. Performing the limit s ≫ m e 2 , we find discrepancies with the earlier results of Ref. [1] and confirm results obtained in Ref. [2] where the effective method of massive operator matrix elements has been used, which works for all but the power corrections in m e 2 / s . In this way, we also confirm the validity of the factorization of massive partons in the Drell-Yan process to O ( α 2 ) . We add non–logarithmic terms at O ( α 2 ) which have not been considered in previous calculations. The final results in the limit s ≫ m e 2 can be given in terms of Nielsen integrals.

We study the thermodynamic properties of a neutral vector boson gas in presence of a constant magnetic field, by means of a semi-classical approach that allows to introduce the spin in the non-relativistic spectrum of the bosons. Bose-Einstein condensation is obtained and it turns out to depend on all the parameters involved in the problem: temperature, particle density and magnetic field. A spontaneous magnetization appears at low temperature as a consequence of the condensed state. The axial symmetry imposed in the system by the magnetic field presence, splits the pressure in two components, one along and another perpendicular to the magnetic axis. Under certain conditions, the perpendicular pressure becomes negative signaling that the system undergoes a transversal magnetic collapse. The spontaneous magnetization might be useful to model magnetic field production inside compact stars, while the negative pressures imposes certain limits to the temperatures and densities needed inside these objects to support a given magnetic field.

We discuss the $\gamma \to \rho^0$ impact factor, i.e., the transition amplitude of a photon to a neutral vector meson $\rho^0$, where the transition is mediated by the two $t$-channel gluons. The impact factor is a building block in the QCD descriptions of high-energy exclusive processes like $\gamma p \to \rho^0 p$, and $\gamma\gamma \to \rho^0 \rho^0$, in particular, for the forward production of $ \rho^0$. The impact factor for the longitudinal polarization of the vector meson obeys the QCD factorization, while the factorization is known to break down for the transverse polarization, indicating that the impact factor for the transversely polarized vector meson is dominated by the ``non-factorizable'' soft contributions. We study the $\gamma \to \rho^0$ impact factor constructing the light-cone QCD sum rules for the corresponding amplitudes, which allow us to estimate the relevant soft contributions in a largely model-independent way, with the use of dispersion relations and quark-hadron duality.

The thermodynamical properties of a neutral vector boson gas in a constant magnetic field are studied starting from the spectrum given by Proca formalism. Bose Einstein Condensation (BEC) and magnetization are obtained, for the three and one dimensional cases, in the limit of low temperatures. In three dimensions the gas undergoes a phase transition to an usual BEC in which the critical temperature depends on the magnetic field. In one dimension a diffuse condensate appears as for the charged vector boson gas. In both cases, the condensation is reached not only by decreasing the temperature but also by increasing the magnetic field. In three and one dimensions self-magnetization is possible. The anisotropy in the pressures due to axial symmetry imposed to the system by the magnetic field is also discussed. The astrophysical implications are commented., Comment: 17 pages, 6 figures

In this paper, we propose novel strategies for neutral vector variable decorrelation. Two fundamental invertible transformations, namely, serial nonlinear transformation and parallel nonlinear transformation, are proposed to carry out the decorrelation. For a neutral vector variable, which is not multivariate-Gaussian distributed, the conventional principal component analysis cannot yield mutually independent scalar variables. With the two proposed transformations, a highly negatively correlated neutral vector can be transformed to a set of mutually independent scalar variables with the same degrees of freedom. We also evaluate the decorrelation performances for the vectors generated from a single Dirichlet distribution and a mixture of Dirichlet distributions. The mutual independence is verified with the distance correlation measurement. The advantages of the proposed decorrelation strategies are intensively studied and demonstrated with synthesized data and practical application evaluations.

I present a scenario wherein heavy neutral vector bosons Z', predicted by GUT-inspired U(1)' models, decay into supersymmetric final states, besides the Standard Model channels investigated at the LHC. It is found that accounting for such decays lowers the exclusion limits on the Z' mass at 13 TeV by about 200-300 GeV., Comment: 5 pages, 6 figures. Talk given at DIS 2017, April 3-7 2017, Birmingham, UK. Minor changes, one reference fixed

We study the equation of motion of neutral vector bosons bearing a magnetic moment (MM). The effective rest mass of vector bosons is a decreasing function of the magnetic field intensity. Consequently a diffuse condensation of the bosons appears below a critical value of the field. For typical values of densities and magnetic fields the magnetization is positive and the neutral boson system can maintain a magnetic field self-consistently. A discussion of the relevance in astrophysics is presented., Comment: 8 pages, 4 figures

The current view about the mixing of heat and salt in the ocean is that it should be parameterised by means of a rotated diffusion tensor based on mixing directions parallel and perpendicular to the local neutral vector. However, the impossibility to construct a density variable in the ocean that is exactly neutral because of the coupling between thermobaricity and density-compensated temperature/salinity anomalies implies that the effective diapycnal diffusivity experienced by any possible density variable is partly controlled by isoneutral diffusion when using neutral rotated diffusion. Here, this effect is quantified by evaluating the effective diapycnal diffusion coefficient for five widely used density variables: Jackett and McDougall (1997) $\gamma^n$, Lorenz reference state density $\rho_{ref}$ of Winters et al. (1996), Saenz et al. (2015), and three potential density variables $\sigma_0$, $\sigma_2$ and $\sigma_4$.Computations use the World Ocean Circulation Experiment climatology, assuming either a uniform value for isoneutral mixing or spatially varying values inferred from an inverse calculation. Isopycnal mixing contributions to the effective diapycnal mixing yields values systematically larger than $10^{-3}$ $\text{m}^2/\text{s}$ in the deep ocean for all density variables, with $\gamma^n$ suffering the least from the isoneutral control of effective diapycnal mixing, and $\sigma_0$ the most. These high values are due to spatially localised large values of non-neutrality, mostly in the deep Southern Ocean. Removing only 5\% of these high values on each density surface reduces the effective diapycnal diffusivities to less than $10^{-4}$ $\text{m}^2/\text{s}$. This work highlights the potential pitfalls of estimating diapycnal diffusivities by means of Walin-like water masses analysis or in using Lorenz reference state for diagnosing spurious numerical diapycnal mixing., Comment: 17 pages, 4 Figures, first draft of a paper submitted to Ocean Sciences 13 July 2017

The inclusive production of the neutral vector mesons K-*0(892) and phi(1020), and of the tensor meson K-2(*0)(1430), in hadronic decays of the Z has been mea sured by the DELPHI detector at LEP. The average production rates per hadronic Z decay have been determined to be 0.77 +/- 0.08 K-2(*0)(892), 0.104 +/- 0.008 phi(1020) and 0.079 +/- 0.040 K-2(*0)(1430). The ratio of the tensor-to-vector meson production yields, [K-2(*0)(1430)]/[K-*0(892)] = 0.10 +/- 0.05, is smaller than the [f(2)(1270)]/[rho(0)(770)] and [f'(2)(1525)]/[phi(1020)] ratios measured by DELPHI. The production rates and differential cross sections are compared with the predictions of JETSET 7.4 tuned to the DELPHI data and of HERWIG 5.8. The K-*0(892) and phi(1020) data are compatible with model predictions, but a large disagreement is observed for the K-2(*0)(1430).

We calculate all neutral vector two-point functions in Chiral Perturbation Theory (ChPT) to two-loop order and use these to estimate the ratio of disconnected to connected contributions as well as contributions involving the strange quark. We extend the ratio of $-1/10$ derived earlier in two flavour ChPT at one-loop order to a large part of the higher order contributions and discuss corrections to it. Our final estimate of the ratio disconnected to connected is negative and a few % in magnitude., 16 pages, one reference added, small changes in table 1, version to be published in JHEP

In this work the neutral-current scattering cross-section for neutrinos on electrons is calculated assuming that a massive Dirac neutrino is characterized by a phenomenological parameters, a charge radius 2> and the right-handed currents are present in the framework of a Left-Right symmetric model (LR). Using the CHARM II result for the charge radius of the muon-neutrino |2>|＜6.0×10-33cm2, we place a bound on -7.9×10-33cm2≤2>LR≤7.9×10-33cm2. We discuss the relationship between the electron neutral couplings gVeV and gVeA and the LR model parameters. We also estimate a bound on the heavy massive neutral vector boson mass MZR＞650GeV of the LR model. These results have never been reported in the literature before and could have practical or theoretical interest, such as in the case of the neutrinos produced in core-collapse supernova explosions, that is to say, right-handed Dirac neutrinos emission from supernova core vLe-→vRe-.

A simple, but fully-covariant model for describing neutral Vector Mesons, in both light and heavy sectors, is briefly illustrated. The main ingredients of our relativistic constituent model are i) an Ansatz for the Bethe-Salpeter vertex for Vector Mesons, and ii) a Mandelstam-like formula for the electromagnetic decay widths. The free parameters of our approach are fixed through a comparison with the valence transverse-momentum distribution, $n(k_\perp)$, obtained within phenomenological Light-Front Hamiltonian Dynamics models reproducing the mass spectra. Preliminary results for the transverse-momentum distributions, the parton distribution and the electromagnetic decay constants are shown., 6 pages, 4 figures. Proceedings of LC2009, to appear in Nucl. Phys. B suppl

In the design of brain-computer interface systems, classification of Electroencephalogram (EEG) signals is the essential part and a challenging task. Recently, as the marginalized discrete wavelet transform (mDWT) representations can reveal features related to the transient nature of the EEG signals, the mDWT coefficients have been frequently used in EEG signal classification. In our previous work, we have proposed a super-Dirichlet distribution-based classifier. The proposed classifier performed better than the state-of-the-art support vector machine-based classifier. In this paper, we further study the neutrality of the mDWT coefficients. The mDWT coefficients have unit L1-norm and all the elements are nonnegative. Assuming the mDWT vector coefficients to be a neutral vector, we apply the proposed parallel nonlinear transformation (PNT) framework to transform them non-linearly into a set of independent scalar coefficients. Based on these scalar coefficients, feature selection strategy is proposed on the transformed feature domain. Experimental results show that the feature selection strategy helps improving the classification accuracy.

We calculate the correlators of vector and axial currents in external strong abelian magnetic field in SU(3) gluodynamics. From the correlators the masses (ground state energies) of neutral ρ and a 1 and charged ρ mesons have been calculated depending on its spin projection on the axis of external magnetic field. The energies of neutral vector mesons with zero spin decrease, while the energies of neutral vector and axial mesons with nonzero spin increase as a function of the field value. Also we show the splitting of the ground state energy for the charged ρ ± mesons in external magnetic field.

We have searched for neutrinoless τ lepton decays into lhh or l V0, where l stands for an electron or muon, h for a charged light hadron, π or K, and V0 for a neutral vector meson, ρ0, K* (892)0 and φ{symbol}, using a 158 fb-1 data sample collected with the Belle detector at the KEKB e+ e- collider. Since the number of events observed are consistent with the expected background, we set upper limits on the branching fractions in the range of (1.6 - 8.0) × 10-7 for various decay modes at the 90% confidence level. © 2006 Elsevier B.V. All rights reserved.

Some 3-3-1 models predict the existence of a non-perturbative regime at the TeV scale. We study in these models, and their supersymmetric extensions, the energy at which the non-perturbative limit and a Landau-like pole arise. An order of magnitude for the mass of the extra neutral vector boson, $Z^\prime$, present in these models is also obtained., Comment: 17 pages, 1 figure, extended version

An extension of the standard model to the local gauge group $SU(3)_c\otimes SU(4)_{\mathrm {L}}\otimes U(1)_X$ as a three-family model is presented. The model does not contain exotic electric charges and we obtain a consistent mass spectrum by introducing an anomaly-free discrete Z 2 symmetry. The neutral currents coupled to all neutral vector bosons in the model are studied. By using experimental results from the CERN LEP, SLAC Linear Collider and atomic parity violation data we constrain the mixing angle between two of the neutral currents in the model and the mass of the additional neutral gauge bosons to be $-0.0032\leq\sin\theta\leq 0.0031$ and $0.67 \hbox{TeV}\leq M_{Z_2} \leq 6.1$ TeV at $95 \%$ C.L., respectively.

We present an analysis of nonperturbative contributions to the transverse momentum distribution of $Z/\gamma^*$ bosons produced at hadron colliders. The new data on the angular distribution $\phi^*_\eta$ of Drell-Yan pairs measured at the Tevatron is shown to be in excellent agreement with a perturbative QCD prediction based on the Collins-Soper-Sterman (CSS) resummation formalism at NNLL accuracy. Using these data, we determine the nonperturbative component of the CSS resummed cross section and estimate its dependence on arbitrary resummation scales and other factors. With the scale dependence included at the NNLL level, a significant nonperturbative component is needed to describe the angular data., Comment: 36 pages, 10 figures, regular article. Revised version accepted for a publication in Phys.Rev.D

The KLOE detector, operating at the DAΦNE ϕ-factory facility of INFN Frascati, has contributed in several ways to the confirmation of the Standard Model, while searching at the same time for direct or indirect hints for new physics signals. Among those, I will discuss briefly the long-standing effort for the precise determination of the hadronic contribution to the muon magnetic anomaly, and the searches for a new, light, neutral vector boson.

Leptonic decay widths and the corresponding decay constants of neutral vector mesons are calculated in the framework of a square-root potential model of independent quarks. Starting with the assumption that a strong correlation exists between the momenta of the quark and anti-quark inside the meson so as to have their total momenta identically zero in the center-of-mass frame of the meson, we find the quark and anti-quark momentum distribution amplitude which is used to determine the transition probability amplitude for the leptonic decay of mesons. The calculated results for leptonic decay widths and the electromagnetic decay constants for the vector mesons \rho, \omega, \phi and \psi are in good agrement with the corresponding experimental values. The results for the heavy meson \Upsilon are somewhat lower than the experimental values.

We consider the contributions of individual new particles to the anomalous magnetic moment of the muon, utilizing the generic framework of simplified models. We also present analytic results for all possible one-loop contributions, allowing easy application of these results for more complete models which predict more than one particle capable of correcting the muon magnetic moment. Additionally, we provide a Mathematica code to allow the reader straightforwardly compute any 1-loop contribution. Furthermore, we derive bounds on each new particle considered, assuming either the absence of other significant contributions to $a_\mu$ or that the anomaly has been resolved by some other mechanism. The simplified models we consider are constructed without the requirement of $SU(2)_L$ invariance, but appropriate chiral coupling choices are also considered. In summary, we found the following particles capable of explaining the current discrepancy, assuming unit couplings: $2$~TeV ($0.3$~TeV) neutral scalar with pure scalar (chiral) couplings, $4$~TeV doubly charged scalar with pure pseudoscalar coupling, $0.3-1$~TeV neutral vector boson depending on what couplings are used (vector, axial, or mixed), $0.5-1$~TeV singly-charged vector boson depending on which couplings are chosen, and $3$~TeV doubly-charged vector-coupled bosons. We also derive the following $1\sigma$ lower bounds on new particle masses assuming unit couplings and that the experimental anomaly has been otherwise resolved: a doubly charged pseudo-scalar must be heavier than $7$~TeV, a neutral scalar than $3$~TeV, a vector-coupled new neutral boson $600$~GeV, an axial-coupled neutral boson $1.5$~TeV, a singly-charged vector-coupled $W^\prime$ $1$~TeV, a doubly-charged vector-coupled boson $5$~TeV, scalar leptoquarks $10$~TeV, and vector leptoquarks $10$~TeV., Comment: Public Mathematica Code (arxiv source files). 32 pages, 6 Figures. To appear in PRD

By considering left-right (L-R) asymmetries we study the capabilities of lepton colliders in searching for new exotic vector bosons. Specifically we study the effect of a doubly charged bilepton boson and an extra neutral vector boson appearing in a 3-3-1 model on the L-R asymmetries for the processes $e^-e^-\to e^-e^-$, $\mu^-\mu^-\to\mu^-\mu^-$ and $e^-\mu^-\to e^-\mu^-$ and show that these asymmetries are very sensitive to these new contributions and that they are in fact powerful tools for discovery this sort of vector bosons., Comment: RevTeX, 22 pages, 12 eps figures

In a class of E6 inspired models with a light additional neutral vector boson, we discuss the effects of the magnetic moment of the tau neutrino by analyzing [Formula: see text] at the Z-pole. We take into account present scenarios for the extra Abelian group and vary extra neutral gauge boson mass beyond the present experimental exclusion limits. The present LEP experimental results prove that we can set an upper bound on the magnetic moment of the tau neutrino: κντ≤ 1.83× 10-6.

We study a fewF ¼ 2 andF ¼ 1 flavor-changing neutral current processes in the minimal 3-3-1 model by considering, besides the neutral vector bosons Z 0 , the effects due to one CP-even and one CP-odd scalar. We find that there are processes in which the interference among all the neutral bosons is constructive or destructive and in others the interference is negligible. We first obtain numerical values for all the unitary matrices that rotate the left- and right-handed quarks and give the correct mass of all the quarks in each charge sector and the Cabibbo-Kobayashi-Maskawa (CKM) mixing matrix. The so-called 3-3-1 models with gauge symmetry SUð3ÞCSUð3ÞLUð1ÞX are interesting extensions of the standard model (SM). The main feature of these models is that, by choosing appropriately the representation con- tent, the triangle anomalies cancel out, and the number of families has to be a multiple of three. Moreover, because of the asymptotic freedom, this number is just three (1-3). In particular, the minimal version of this class of models (m3- 3-1 for short) (1) has other interesting predictions: It ex- plains why sin 2 � W < 1=4 is observed, and at the same time, when sin 2 � W ¼ 1=4, it implies the existence of a Landau-like pole at energies of the order of a few TeVs (4). The existence of this Landau-like pole also stabilizes the electroweak scale avoiding the hierarchy problem (5), and the model allows the quantization of electric charge inde- pendently of the nature of the massive neutrinos (6,7). It also has an almost automatic Peccei-Quinn symmetry if the trilinear term in the scalar potential becomes a dynamical degree of freedom (8), there are also new sources of CP violations which allow to obtainand � 0 =� even without the Cabibbo-Kobayashi-Maskawa (CKM) phase; i.e., if we put � ¼ 0 (9). And, probably, it could explain CPviolation in the B � B mesons as well. One important feature that distinguishes the model from any other one is the predic- tion of extra singly charged and doubly charged gauge boson bileptons (10) and also exotic charged quarks, while the lepton sector is the same as that of the SM. Right- handed neutrinos are optional in the model. They are not needed to generate light active neutrinos or the Pontecorvo-Maki-Nakagawa-Sakata (PMNS) mixing ma- trix. Those exotic charged particles may have an effect on the two photon decay of the SM-like Higgs scalar (11). A common feature of all 3-3-1 models is that two of the quark triplets transform differently from the third one, and this implies flavor-changing neutral currents (FCNC) at tree level mediated by the extra neutral vector boson, Z 0

We assume the latest experimental determination of the weak charge of atomic cesium and analyze its implications for possible new physics. We notice that the data would imply positive upper and lower bounds on the new physics contribution to the weak charge, $\delta_NQ_W$. The required new physics should be of a type not severely constrained by the high energy precision data. A simplest possibility would be new neutral vector bosons almost un-mixed to the $Z$ and with sizeable couplings to fermions. The lower positive bound would however forbid zero or negative $\delta_NQ_W$ and exclude not only the standard model but also models with sequential $Z^\prime$, in particular simple-minded towers of $Z$-like excitations from extra-dimensions. The bound would also imply an upper limit on the $Z^\prime$ mass within the models allowed. Conclusions are also derived for models of four-fermion contact interactions., Comment: 11 pages, Latex, 1 PS figure, final version for Physics Letters

Strong solvability in Sobolev spaces W 2, p (Ω) is proved for the regular oblique derivative problem for second order uniformly elliptic operators with VMO-principal coefficients. The results are applied to the study of degenerate (tangential) oblique derivative problem in the case of neutral vector field on the boundary.

Dilepton production from meson condensed hadronic matter is studied based on the vec­ tor meson dominance (VMD) hypothesis, where the hadronic electro-magnetic (EM) current is a linear combination of the neutral vector meson fields. In the presence of the pseudo-scalar meson condensate, the vector and the axial-vector mesons are mixed to form quasi-particles, and the hadronic EM current is proved to be a linear combination of the quasi-particle fields of the "vector" and the "axial-vector". As a result, we find that an axial-vector-like contri­ bution appears in the dilepton spectrum from the meson condensed matter. For two cases, the pion and the kaon condensations, we explicitly calculate the electron-pair spectrum and discuss its characteristic modifications.

We argue that a Regge-pole modification of the VDM puts on equal footing the asymptotic behaviour of electromagnetic and neutral vector meson currents., Comment: 4 pages

Searches for new, light, neutral vector particles are being pursued by several different experiments in the world, using e+e− collsion data at center-of-mass energies ranging between ∼1 and ∼10 GeV. In this paper I will review the most recent results from KLOE, BESIII, BaBar and Belle and briefly discuss open issues and future perspectives in the field.

We study in a model-independent way new neutral and charged vector bosons that could give observable signals with leptonic final states at the LHC. We show, in particular, that a charged vector W' decaying into lepton plus neutrino is accompanied by at least an extra neutral vector boson Z', nearly degenerate with the charged one. Conversely, a Z' boson with significant isospin violation cannot exist without a companion W'. To take advantage of these generic correlations, we perform a combined analysis of LHC data in the dilepton and lepton-plus-missing-energy channels, which allows us to improve the limits from independent analyses. We also develop some tools to easily deal with cases in which several heavy vector bosons with similar masses interfere. Finally, we develop a theoretically consistent framework for the study of the sequential Z' and W' benchmarks., Comment: pdfLateX, 36 pages, 11 figures. Minor changes, version published in Journal of High Energy Physics

The role of high-frequency transients in the maintenance of planetary-scale flow regimes is investigated using a generalization of the neutral vector approach developed by Marshall and Molteni. Given a nonlinear dynamical model of the atmospheric motion, neutral vectors were defined as the axes with the smallest linear time derivative, computed by linearizing the equations of motion around the time-mean state of the system. If the nonlinear model possesses (at least) two steady states associated with nearly equally populated regimes, then the anomaly fields corresponding to the steady states strongly project onto the subspace spanned by the neutral vectors. The study of the simple nonlinear models with multiple steady solutions suggests that the nonlinear self-interactions of the high-frequency transients within each regime can shift the phase-space position of the regime mean state (or centroid) from the position of the corresponding steady state. If the feedback of high-frequency transients ont...

An exotic annihilation of e+e− at rest into a single γ and a weakly interacting neutral vector boson V0 was searched for by measuring the related γ energy under the condition that no additional γ was detected by a hermetic detector. No evidence of such an annihilation was observed, resulting in the upper limits on the branching ratio of 4.2 × 10−6 (mV0 < 200 keV/c2) and 2.1 × 10−5 (mV0 < 2me = 1022 keV/c2). These upper limits were converted to those on the branching ratio of an exotic three-body decay (γγV0) of orthopositronium (o-Ps), i.e. 6.2 × 10−6 (mV0 < 200 keV/c2) and 1.7 × 10−5 (mV0 < 2me). As a result, this mode was definitely excluded as the source of the reported discrepancy in the o-Ps decay rate.