A conformally invariant hidden sector is considered, with a scalar operator $O$ of low dimension that couples to the electro-weak gauge bosons of the Standard Model, via terms such as $O F^{μν}F_{μν}$. By examining single photon production at LEP, we bound the strength of these interactions. We apply our results, along with those of Delgado and Strassler and of Caracciolo and Rychkov, to improve the bound on four-photon production through "unparticle self-interactions", as proposed by Feng et al. We find the maximum allowable cross-section is of order a few tens of femtobarns at the 14 TeV LHC, and lies well below 1 fb for a wide range of parameters.
The oblique parameters $S$ and $T$ are calculated in a gauged unparticles model based on the electroweak group $SU(2)*U(1)$ and it's parameters space is constrained using electroweak precision measurements.
We study the possible annihilation cross section of scalar dark matter and its coupling λ_D to the standard model Higgs in the case of the electroweak symmetry breaking driven by unparticle. Here the annihilation process occurs with the help of three intermediate scalars which appear after the mixing. By respecting the annihilation rate which is compatible with the current relic density we predict the tree level coupling λ_D. We observe that the unparticle scaling d_u plays a considerable role on the annihilation process and, therefore, on the coupling λ_D.
我们表明，标量非粒子耦合到标准模型希格斯在重整化水平可以有一个戏剧性的影响，在打破的电弱对称性已经在树的水平。特别是人们可以得到适当的电弱标度，而不需要在拉格朗日中的希格斯质量项。通过研究混合的非粒子-希格斯传播子和谱函数，我们还展示了非粒子如何使希格斯质量偏离其标准模型值λ v ^2，并影响其他希格斯玻色子的性质。相反，我们详细研究了电弱对称破缺如何通过破坏其共形对称性和产生质量间隙来影响非粒子扇区。我们还表明，对于希格斯质量以上的差距，非粒子可以增加相当显着的希格斯宽度。
我们提出了一个通用的框架中，希格斯和非粒子都是复合材料。其基础理论是四维、渐近自由、非超对称的含费米子物质的规范理论。我们勾勒出一个可能的统一，这两个部门在一个更高的规模类似于扩展的彩色模型。通过构造，我们的扩展是自然的，这意味着没有层次问题。非粒子扇区与复合希格斯玻色子的耦合表现为一个四费米子算符。电弱标度附近的双线性非粒子算符的标度维数在1 < dU < 3的范围内。我们调查，在不同的方式，打破规模不变性引起的电弱规模导致非粒子凝聚。后者作为一个自然的红外截止或强子尺度。我们给出了在电弱标度附近有效的低能有效理论。非粒子的希格斯混合被发现在我们的框架内被抑制。
The magnetic dipole moment (MDM) and the electric dipole moment (EDM) of leptons are calculated under the assumption of lepton flavor violation (LFV) induced by spin-1 unparticles with both vector and axial-vector couplings to leptons,including a CP-violating phase. The experimental limits on the muon MDM and LFV process such as the decay l_i->i_jl_kl_k are then used to constrain the LFV couplings for particular values of the unparticle operator dimension d_U and the unparticle scale Λ_U, assuming that LFV transitions between the tau and muon leptons are dominant. It is found that the current …
The exclusive production pp->pXp is known to be one of the most clean channels at the LHC. We investigate the potential of processes pp -> p l-l+ p and pp-> p gamma gamma p to probe scalar and tensor unparticles by considering three different forward detector acceptances; 0.0015<xi<0.15, 0.0015<xi<0.5 and 0.1<xi<0.5. We obtain 95% confidence level sensitivity limits on the unparticle couplings for various integrated luminosities.
In this work, we study the possible unparticle signatures through tau pair production e+e- -> tau+tau- process at the low energy particle factories. We take into account lepton flavor conserving (s-channel) and violating (t-channel) couplings for the unparticle leptonic interactions. For different values of the scaling parameter d we extract upper limits on the scalar unparticle couplings at the integrated luminosities of 100/fb.yr and 1 ab/fb.yr.
We have constrained unparticle interactions with neutrinos and electrons using available data on neutrino-electron elastic scattering and the four CERN LEP experiments data on mono photon production. We have found that, for neutrino-electron elastic scattering, the MUNU experiment gives better constraints than previous reported limits in the region d>1.5. The results are compared with the current astrophysical limits, pointing out the cases where these limits may or may not apply. We also discuss the sensitivity of future experiments to unparticle physics. In particular, we show that the measu…
We perform a global fit on parity-conserving electron-quark interactions via spin-1 unparticle exchange. Besides the peculiar features of unparticle exchange due to non-integral values for the scaling dimension d_U and a non-trivial phase factor exp (-id_U π) associated with a time-like unparticle propagator, the energy dependence s^{-2 + d_U} of the unparticle contributions in the scattering amplitudes are also taken into account. The high energy data sets taken into consideration in our analysis are from (1) deep inelastic scattering at high Q^2 from ZEUS and H1, (2) Drell-Yan production at …
Unitarity, a powerful constraint on new physics, has not always been properly accounted for in the context of hidden sectors. Feng, Rajaraman and Tu have suggested that large (pb to nb) multi-photon or multi-lepton sugnals could be generated at the LHC through the three-point functions of a conformally-invariant hidden sector (an "unparticle" sector.) Because of the conformal invariance, the kinematic distributions are calculable. However, the cross-sections for many such processes grow rapidly with energy, and at some high scale, to preserve unitarity, conformal invariance must break down. Re…
Neutrino-electron scatterings are purely leptonic processes with robust Standard Model (SM) predictions. Their measurements can therefore provide constraints to physics beyond SM. The $\nuebar$-e data taken at the Kuo-Sheng Reactor Neutrino Laboratory were used to probe two scenarios: Non-Standard Neutrino Interactions (NSI) and Unparticle Physics. New constraints were placed to the NSI parameters ($\el$,$\er$) and ($\etl$,$\etr$) for the Non-Universal and Flavor-Changing channels, respectively, as well as to the coupling constants for scalar ($λ_0$) and vector ($λ_1$) unparticles to the neutr…
Neutrino-electron scattering is a purely leptonic fundamental interaction and therefore provides an important channel to test the Standard Model, especially at the low energy-momentum transfer regime. We derived constraints on neutrino nonstardard interaction couplings depending on model-independent approaches which are described by a four-Fermi pointlike interaction and unparticle physics model with tensorial components. Data on $\barν_{e}-e$ and $ν_{e}-e$ scattering from the TEXONO and LSND experiments, respectively, are used. The upper limits and the allowed regions of scalar, pseudoscalar,…
We study the effects of fermiophobic scalar/pseudo-scalar oblique corrections on bound state energy levels in muonic atoms. To make the treatment sufficiently general we will consider Unparticle scalars/pseudo-scalars which couple only to photons. We derive the relevant vacuum polarization functions and comment on the functional forms of the Unparticle Uehling potentials for various scaling dimensions in the point nucleus and finite nucleus approximations. It is estimated that for an infra-red fixed point near the scale of electroweak symmetry breaking, in the low TeV range, the energy shifts …
A new representation of electroweak lepton sector is proposed. It consists of two Weyl spinors per one lepton family. It is shown that proposed representation is fully equivalent to the conventional left-handed iso-doublet. New type of plane wave solutions can be found under certain additional assumptions.
Since the {\tt KKMC} program was published for the first time over 20 years ago, it has gained popularity and was exploited in a broad spectrum of applications. The core part of the program itself did not change much. In contrast, some of the libraries have evolved substantially. The aim of this publication is to archive four versions, alternative to the one published 20 years ago versions of the electroweak libraries (or just parameter initialization versions), which were instrumental for the precision Standard Model calculation from the end of LEP era till now and for the sake of the future …
We report on our calculation of next-to-leading-order electroweak corrections to W-boson pair production at the LHC, taking into account off-shell effects and spin correlations of the W bosons and their leptonic decays in the framework of a double-pole approximation. We study the various contributions to the electroweak corrections in detail and discuss their impact on selected observables within a realistic event-selection setup.
I suggest an extension of the SM by introducing a dark sector with the local $U(1)_{D}$ symmetry. The particles in the dark sector bring about the new physics beyond the SM. In particular the global $B-L$ symmetry is violated just above the electroweak scale, this becomes a common origin of the tiny neutrino mass, the cold dark mater and the baryon asymmetry. The model can not only account for the tiny neutrino mass and the "WIMP Miracle", but also achieve the leptogenesis around the electroweak scale. Finally, it is very possible that the model predictions are tested in near future experiment…
We present the first calculation of the next-to-leading-order electroweak corrections to W-boson + jet hadroproduction including leptonic W-boson decays. The W-boson resonance is treated consistently using the complex-mass scheme, and all off-shell effects are taken into account. The corresponding next-to-leading-order QCD corrections have also been recalculated. All the results are implemented in a flexible Monte Carlo code. Numerical results for cross sections and distributions of this Standard Model benchmark process are presented for the Tevatron and the LHC.
We study phenomenological consequences of the strong first-order electroweak phase transition in an extension of the standard model with an inert doublet and vector-like leptons motivated by the muon $g-2$ anomaly and dark matter. We find that a condition for the strong first-order electroweak phase transition inevitably induces a large logarithmic enhancement in $Z$ boson decays, which relegates the explanation of the anomalous muon $g-2$ at below 2$σ$ level. Our analysis shows that future lepton collider experiments, especially the Giga-$Z$ at the International Linear Collider and Tera-$Z$ a…
The origin of the matter-antimatter asymmetry in the Universe is a fundamental question of physics. Electroweak baryogenesis is a compelling scenario for explaining it but it requires beyond the Standard Model sources of the CP symmetry violation. The simplest possibility is CP violation in the third generation fermion Higgs couplings, widely investigated theoretically and searched for experimentally. It has been found that the experimental bounds on the CP violation in the quark Yukawa couplings exclude their significant role in the electroweak baryogenesis, but it can be still played by the …
This talk summarizes the first calculation of the next-to-leading-order electroweak corrections to W-boson + jet hadroproduction including leptonic W-boson decays [1]. The W-boson resonance is treated consistently using the complex-mass scheme, and all off-shell effects are taken into account. The corresponding next-to-leading-order QCD corrections have also been recalculated. All the results are implemented in a flexible Monte Carlo code. Selected numerical results for this Standard Model benchmark process are presented for the LHC.
This paper presents the high-precision theoretical predictions for $e^+e^- \to l^-l^+$ scattering. Calculations are performed using the {\tt SANC} system. They take into account complete one-loop electroweak radiative corrections as well as longitudinal polarization of initial beams. Reaction observables are obtained using the helicity amplitude method with taking into account initial and final state fermion masses. Numerical results are given for the center-of-mass energy range $\sqrt{s}=250-1000$ GeV with various degrees of polarization.
We present next-to-leading order (NLO) electroweak corrections to the dominant five angular coefficients parametrizing the Drell-Yan process in the $Z$-boson mass peak range for finite-$p_T$ vector boson production. The results are presented differentially in the vector boson transverse momentum. The Lam-Tung violating difference $A_0-A_2$ is examined alongside the coefficients. A single lepton transverse momentum cut is needed in the case of electroweak corrections to avoid a double singularity in the photon induced diagrams, and the dependence on the value of this cut is examined. We compare…
For the first time the next-to-leading-order electroweak corrections to the full off-shell production of two top quarks that decay leptonically are presented. This calculation includes all off-shell, non-resonant, and interference effects for the 6-particle phase space. While the electroweak corrections are below one per cent for the integrated cross section, they reach up to 15% in the high-transverse-momentum region of distributions. To support the results of the complete one-loop calculation, we have in addition evaluated the electroweak corrections in two different pole approximations, one…
