Search

The sensitivity to anomalous quartic gauge couplings (AQGCs) of the $\gamma\gamma\gamma Z$ interaction is studied in the $\mu^+\mu^- \rightarrow \mu^+\gamma\gamma \mu^-$ scattering at a future muon collider with unpolarized beams. The anomalous $\gamma\gamma\gamma Z$ vertex is described by two couplings, $\zeta_1$ and $\zeta_2$. The differential and total cross sections are calculated for the center-of-mass energies of 3 TeV, 14 TeV, and 100 TeV. For these values of the collision energy the $95\%$ C.L. exclusion regions for AQGCs are obtained depending on the systematic error. In particular, for the 14 TeV muon collider with the integrated luminosity $L = 20$ ab$^{-1}$ the best sensitivities are derived to be $\zeta_1 = 3.1 \times 10^{-5}$ TeV$^{-4}$ and $\zeta_2 = 6.5 \times 10^{-5}$ TeV$^{-4}$. These constraints are three orders of magnitude stronger than the bounds obtained for the 27 TeV HE-LHC with $L = 15$ ab$^{-1}$. At the 100 TeV muon collider with $L = 1000$ ab$^{-1}$ AQGCs can be probed up to $(1.64 \div 3.4) \times 10^{-8}$ TeV$^{-4}$. The partial-wave unitarity constraints on couplings $\zeta_1$, $\zeta_2$ are evaluated. It is shown that the unitarity is not violated in the region of the AQGCs examined in the present paper., Comment: 23 pages, 6 figures

We have studied anomalous four-photon couplings in the $\mu^+\mu^- \rightarrow \mu^+ \gamma\gamma \mu^-$ scattering at a future muon collider. The collision energies of 3 TeV, 14 TeV, and 100 TeV are addressed. Both differential and total cross sections versus invariant mass of the outgoing photons are calculated. The best 95\% C.L. exclusion bounds on anomalous couplings are obtained to be $g_1 = 2.23 \times 10^{-8}$ TeV$^{-4}$ and $g_2 = 4.22 \times 10^{-8}$ TeV$^{-4}$. They correspond to the muon collision energy of 100 TeV. The partial-wave unitary constraints on $g_1$ and $g_2$ are examined. We have demonstrated that the unitarity is not violated in a region of the anomalous couplings obtained in the present paper., Comment: 26 pages, 6 figures, two equations with comments and one reference are added

We have examined inclusive $\mu^+\mu^- \rightarrow \mu^+ \mu^- + E_{\mathrm{miss}}$ and annihilation $\mu^+\mu^- \rightarrow \mu^+ \mu^-$ processes at future high energy muon colliders in the framework of the Randall-Sundrum-like model with a small curvature of space-time. The collision energies of 3 TeV, 14 TeV and, 100 TeV are addressed. Both differential and total cross sections are calculated, and exclusion bounds on a 5-dimensional gravity scale are obtained depending on collision energy and integrated luminosity of the muon colliders., Comment: 31 pages, 10 figures, one figure with comments and two appendices are added

We have examined the sensitivity to the axion-like particle (ALP) couplings to electroweak gauge bosons in the diphoton production at a future muon collider. The collisions at the $\mu^+ \mu^-$ energies of 3 TeV, 14 TeV, and 100 TeV are addressed. The differential cross sections versus the invariant mass of the final photons and total cross section versus minimal diphoton invariant mass are presented. We have derived the exclusion regions for the ALP-gauge boson coupling. The obtained bounds are much stronger than the current experimental bounds in the ALP mass region 10 GeV -- 10 TeV. The partial-wave unitarity constraints on the ALP-gauge boson coupling are estimated. We have shown that the unitarity is not violated in the region of the ALP coupling studied in the present paper., Comment: 30 pages, 6 figures

The noncommutative QED (NCQED) has a non-Abelian nature due to the presence of 3- and 4-photon vertices in the lagrangian. Thus, NCQED predicts a new physics contribution to the $\gamma\gamma\rightarrow\gamma\gamma$ scattering already at the tree level. We have examined NCQED by studying the light-by-light process at the 14 TeV LHC with intact protons. Our results show that the NC scale up to $\Lambda_{\mathrm{NC}} = 1.65(1.35)$ TeV can be probed in the $pp\rightarrow p(\gamma\gamma)p \rightarrow p'(\gamma\gamma)p'$ collision for the time-space (space-space) NC parameters. These bounds are stronger than the limits that can be obtained in the light-by-light scattering at high energy linear colliders., Comment: 26 pages, 5 figures. Two comments and several references are added

For the first time, the production of a massive dark photon (DP) in the $\gamma e^-$ scattering at the future lepton colliders ILC, CLIC, and CEPC is examined. The invisible decay mode of the DP is addressed. We have studied both the unpolarized scattering and the collision of the Compton backscattered photons with the polarized electron. The missing energy distributions are shown. We have considered the wide range 10 GeV -- 1000 GeV of the DP mass $m_{A'}$. The excluded regions at the 95\% C.L. in the plane $(\varepsilon, m_{A'})$, where $\varepsilon$ is the kinetic mixing parameter, are obtained., Comment: 24 pages, 10 figures; one equation and two references are added

We have estimated the sensitivity to the anomalous couplings of the $\gamma\gamma\gamma Z$ vertex in the $\gamma\gamma\rightarrow\gamma Z$ scattering of the Compton backscattered photons at the CLIC. Both polarized and unpolarized collisions at the $e^+e^-$ energies 1500 GeV and 3000 GeV are addressed, and anomalous contributions to helicity amplitudes are derived. The differential and total cross sections are calculated. We have obtained 95\% C.L. exclusion limits on the anomalous quartic gauge couplings (QGCs). They are compared with corresponding bounds derived for the $\gamma\gamma\gamma Z$ couplings via $\gamma Z$ production at the LHC. The constraints on the anomalous QGCs are one to two orders of magnitude more stringent that at the HL-LHC. The partial-wave unitarity constraints on the anomalous couplings are examined. It is shown that the unitarity is not violated in the region of the anomalous QGCs studied in the paper., Comment: 29 pages, 7 figures, 3 tables; minor corrections to the text, 4 references added

The anomalous quartic neutral couplings of the $\gamma\gamma\gamma\gamma$ vertex in a polarized light-by-light scattering of the Compton backscattered photons at the CLIC are examined. Both differential and total cross sections are calculated for $e^+e^-$ collision energies 1500 GeV and 3000 GeV. The helicity of the initial electron beams is taken to be $\pm\,0.8$. The unpolarized and SM cross sections for the same values of helicities are also estimated. The 95\% C.L. exclusion limits on two anomalous photon couplings $\zeta_1$ and $\zeta_2$ are calculated. The best bounds on these couplings are found to be $6.85 \times 10^{-16} \mathrm{\ GeV}^{-4}$ and $1.43 \times 10^{-15} \mathrm{\ GeV}^{-4}$, respectively. The results are compared with the exclusion bounds obtained previously for the LHC and HL-LHC. It is shown that the light-by-light scattering at the CLIC, especially the polarized, has a greater potential to search for the anomalous quartic neutral couplings of the $\gamma\gamma\gamma\gamma$ vertex., Comment: 20 pages, 8 figures. Figures 2-11 are combined as 2-7, tables 2-6 are combined as tables 2-3. Equation (16) is corrected, equations (17), (18), and one reference are added. Abstract is corrected. Version accepted for publication in EPJ C

The light-by-light (LBL) scattering with initial polarized Compton backscattered photons at the CLIC, induced by axion-like particles (ALPs), is investigated. The total cross sections are calculated, assuming CP-even coupling of the pseudoscalar ALP to photons. The 95\% C.L. exclusion region for the ALP mass $m_a$ and its coupling constant $f$ is presented. The results are compared with previously obtained CLIC bounds for the unpolarized case. It is shown that the bounds on $f$ for the polarized beams in the region $m_a = 1000 \mathrm{\ GeV} - 2000 \mathrm{\ GeV}$, with the collision energy 3000 GeV and integrated luminosity 4000 fb$^{-1}$, are on average 1.5 times stronger than the bounds for the unpolarized beams. Herewith, our CLIC bounds are stronger than all current exclusion regions for $m_a > 80$ GeV. In particular, they are more restrictive than the limits which follow from the ALP-mediated LBL scattering at the LHC., Comment: 19 pages, 9 figures. Abstract is corrected. Several formulas are added. Figures 2,3 and 9 are combined into two figures 2 and 3. Summary plot is added. To be published in Chinese Physics C

The virtual production of axion-like particles (ALPs) in the light-by-light scattering at the CLIC collider is studied. Both differential and total cross sections are calculated, assuming interaction of the ALP with photons via CP-odd term in the Lagrangian. The 95\% C.L. exclusion regions for the ALP mass and its coupling constant are given. By comparing our results with existing collider bounds, we see that the ALP search at the CLIC has a great physics potential of searching for the ALPs, especially, in the mass region 1 TeV -- 2.4 TeV, with the collision energy $\sqrt{s} = 3000$ GeV and integrated luminosity $L = 5000$ fb$^{-1}$ for the Compton backscattered initial photons. In particular, our limits are stronger that recently obtained bounds for the ALP production in the light-by-light scattering at the LHC., Comment: 32 pages, 13 figures. Introduction is reduced, figure 11 is corrected. Appendix, several references and some comments are added

The photon-induced dimuon production $e^+ e^- \to e^+ \gamma \gamma e^- \to e^+ \mu^+ \mu^- e^-$ at the CLIC is studied in the framework of three models with extra dimensions. The electron beam energies 750 GeV and 1500 GeV are considered. The total cross sections are calculated depending on the minimal transverse momenta of the final muons. The sensitivity bounds on the parameters of the models are obtained as functions of the CLIC integrated luminosity., Comment: 37 pages, 19 figures. Several formulas with comments are added. Figures 13 and 14 are corrected, figure 19 is added

The LHC possibilities to constrain the parameters of the Randall-Sundrum-like model with one warped extra dimension and small curvature through the diphoton production in the photon-induced process pp -> p gamma gamma p -> p' gamma gamma p' are investigated. Two acceptances of the forward detectors, 0.015 < xi < 0.15 and 0.015 < xi < 0.5, where xi is the fractional proton momentum loss of the incident protons, are considered. The sensitivity bounds on the 5-dimensional gravity scale are obtained as a function of the LHC integrated luminosity., Comment: 20 pages, 8 figures. One equation and several comments are added

In this paper, potential of the LHC to explore the phenomenology of the Randall-Sundrum-like scenario with the small curvature for the process $pp \to p \gamma \gamma p \to p \mu^- \mu^+p $ through the subprocess $\gamma \gamma \to \mu^- \mu^+$ is examined for two forward detector acceptances, $0.0015 < \xi< 0.5$ and $0.1< \xi <0.5$. This process is known to be one of the most clean channels. The sensitivity bounds on the anomalous model parameters have been found at the $95\%$ confidence level for various LHC integrated luminosity values., Comment: 22 pages, 8 figures; 11 equations and 8 references are added

In this study, we investigate the potential of the process $pp\rightarrow p\gamma^{*} p\rightarrow p \tau \bar{\nu}_{\tau}q^{\prime} X$ at the LHC to examine the anomalous electromagnetic moments of the tau lepton. We obtain $95\%$ confidence level bounds on the anomalous coupling parameters with various values of the integrated luminosity and center-of-mass energy. The improved bounds have been obtained on the anomalous coupling parameters of electric and magnetic moments of the tau lepton $a_{\tau}$ and $\vert$$d_{\tau}$$\vert$ compared to the current experimental sensitivity bounds. The $\gamma p$ mode of photon reactions at the LHC have shown that it has great potential for the electromagnetic dipole moments studies of the tau lepton., Comment: 5 pages, 4 Tables, 5 Figures

We have examined the anomalous electromagnetic moments of the tau lepton in the processes $e^{-}\gamma \to \nu_e\tau\bar{\nu}_\tau$ ($\gamma$ is the Compton backscattering photon) and $e^{-}e^{+} \to e^{-}\gamma^* e^{+} \to \nu_{e}\tau \bar{\nu}_\tau e^+$ ($\gamma^*$ is the Weizsacker-Williams photon) with unpolarized and polarized electron beams at the CLIC. We have obtained 95$\%$ confidence level bounds on the anomalous magnetic and electric dipole moments for various values of the integrated luminosity and center-of-mass energy. Improved constraints of the anomalous magnetic and electric dipole moments have been obtained compared to the LEP sensitivity., Comment: 24 pages, 9 figures, published version

We have investigated the anomalous quartic couplings defined by the dimension-8 operators in semileptonic decay channel of the $e^{+}e^{-}\rightarrow \nu_{e} W^{-} W^{+} \bar{\nu}_{e}$ process for unpolarized and polarized electron (positron) beam at the Compact Linear Collider. We give the $95\%$ confidence level bounds on anomalous $\frac{f_{S0}}{\Lambda^{4}}$, $\frac{f_{S1}}{\Lambda^{4}}$ and $\frac{f_{T0}}{\Lambda^{4}}$ couplings for various values of the integrated luminosities and center-of-mass energies. The best sensitivities obtained on anomalous $\frac{f_{S0}}{\Lambda^{4}}$, $\frac{f_{S1}}{\Lambda^{4}}$ and $\frac{f_{T0}}{\Lambda^{4}}$ couplings through the process $e^{+}e^{-}\rightarrow \nu_{e} W^{-} W^{+} \bar{\nu}_{e}$ with beam polarization at $\sqrt{s}=3$ TeV and an integrated luminosity of $L_{int}=2000$ fb$^{-1}$ are $[-4.05;\, 3.67]\times 10^{-12}$ GeV$^{-4}$, $[-3.08; \, 2.12]\times 10^{-12}$ GeV$^{-4}$, $[-1.98; \, 0.64]\times 10^{-13}$ GeV$^{-4}$, which show improvement over the current bounds., Comment: 8 pages, 7 figures and 8 tables, published version

We study the anomalous $WW\gamma$ couplings at the Compact Linear Collider through the processes $e^{+}e^{-}\to W^+W^-$, $e^{-}e^{+} \to e^{-} \gamma^{*} e^{+} \to e^{+} \nu_{e} W^-$ and $e^{-}e^{+}\to e^{-} \gamma^{*} \gamma^{*} e^{+} \to e^{-} W^+ W^- e^{+} $ $ (\gamma^{*}$ is the Weizsacker-Williams photon). We give the 95\% confidence level limits for unpolarized and polarized electron (positron) beam on the anomalous couplings for various values of the integrated luminosities and center-of-mass energies. We show that the obtained limits on the anomalous couplings through these processes can highly improve the current experimental limits. In addition, our limits with beam polarization are approximately two times better than the unpolarized case., Comment: Tables and references added

We have investigated the flavor changing top quark physics on the dimension-six anomalous $tq\gamma$ ($q=u,c$) couplings through the process $pp\to p\gamma \gamma p\to p t\bar{q}p$ at the LHC by considering different forward detector acceptances. In this paper, we have taken into account and examine the effects of top quark decay. The sensitivity bounds on the anomalous couplings and, $t\to q\gamma$ branching ratio have been obtained at the $95\%$ confidence level for the effective lagrangian approach. Besides, we have investigated the effect of the anomalous couplings on single top quark spin asymmetry., Comment: 24 pages, 8 figures. This version matches the published version in Nucl.Phys.B

We have investigated real graviton emission in the ADD and RS model of extra dimensions through the photoproduction process pp-> p gamma p-> pGqX at the LHC. We have considered all contributions from the subprocesses gamma q -> G q, where q=u,d,c,s,b,anti-u,anti-d, anti-c, anti-s, anti-b quark. The constraints on model parameters of the ADD and RS model of extra dimensions have been calculated. During numerical calculations we have taken account of 3, 4, 5 and 6 large extra dimensional scenarios. The constraints on RS model parameters have been calculated by considering G -> gamma gamma, e^- e^+, mu^- mu^+ decay channels of the graviton., Comment: 27 pages, 12 figures; final version to appear in PRD

We investigate the anomalous interactions of heavy up-type quark t' in a $\gamma \gamma$ collision at the LHC. We have obtained 95% confidence level(CL)limit of $t'q \gamma$ anomalous coupling by taking into account three forward detector acceptances: $0.0015<\xi<0.15$,$0.0015<\xi<0.5$, and $0.1<\xi<0.5$., Comment: 16 pages, 3 figures, 3 tables

We have examined the constraints on the anomalous $tq\gamma$ ($q=u,c$) couplings through the process $pp\to p\gamma p\to pWbX$ at the LHC by considering three forward detector acceptances: $0.0015< \xi < 0.5$, $0.0015< \xi <0.15$ and $0.1< \xi < 0.5$. The sensitivity bounds on the anomalous couplings have been obtained at the $95%$ confidence level in a model independent effective lagrangian approach. We have found that the bounds on these couplings can be highly improved compared to current experimental bounds., Comment: 11 pages,9 figures

We have examined TeV scale effects of extra spatial dimensions through the processes gamma q-> gamma q where q=u,d,c,s,b, anti-u, anti-d, anti-c, anti-s, anti-b. These processes have been treated in a photon-proton collision via the main reaction pp-> p gamma p-> p gamma qX at the LHC. We have employed equivalent photon approximation for incoming photon beams and performed statistical analysis for various forward detector acceptances., Comment: 17 pages, 5 figures

We examine the impact of electromagnetic properties of neutrinos on the annihilation of relic neutrinos with ultra high energy cosmic neutrinos for the $\nu \bar{\nu}\to \gamma\gamma$ process. For this process, photon-neutrino decoupling temperature is calculated via effective lagrangian model beyond the standard model. We find that photon-neutrino decoupling temperature can be importantly reduced below the QCD phase transition with the model independent analysis defining electromagnetic properties of neutrinos., Comment: 12 pages, 3 figures, published version

We examine the effect of excited neutrinos on the annihilation of relic neutrinos with ultra high energy cosmic neutrinos for the $\nu \bar{\nu}\to \gamma\gamma$ process. The contribution of the excited neutrinos to the neutrino-photon decoupling temperature are calculated. We see that photon-neutrino decoupling temperature can be significantly reduced below the obtained value of the Standard Model with the impact of excited neutrinos., Comment: 11 pages, 3 figures, published version

We study the lepton flavor violating $\mu^- \to e^{-}2\gamma $ decay induced by the mediation of heavy leptons such as the excited and fourth generation leptons. We have examined the effects of these leptons in the $\mu^- \to e^{-}2\gamma $ decay. We have found that branching ratio of this decay is very sensitive to excited and fourth generation leptons. Furthermore, we have obtained the bounds on model parameters by using the current experimental limit of this decay., Comment: 11 pages, 5 figures

Potential of the LHC to explore the phenomenology of the Kaluza-Klein (KK) tower of gravitons in the scenarios of the Arkani-Hamed, Dimopoulos and Dvali(ADD) model and Randall-Sundrum (RS) model is discussed via the process ${\gamma\gamma \to \gamma\gamma}$ including the Standard Model one loop diagram. The improved constraints on model parameters have been obtained compared to the LEP and Tevatron sensitivity., Comment: 15 pages, 8 figures, version to appear in JHEP

We study the potential of the exclusive $pp\to p\ell^-\ell^+p$ process to probe excited leptons at the LHC which is known to be one of the most clean channel at the hadron colliders. The sensitivity of the model parameters is obtained 95% confidence level by considering three forward detector acceptances; $0.0015< \xi < 0.5$, $0.0015< \xi <0.15$ and $0.1< \xi < 0.5$.

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

We discuss the potential of the photon-induced two lepton final states at the LHC to explore the phenomenology of the Kaluza-Klein (KK) tower of gravitons in the scenarios of the Arkani-Hamed, Dimopoulos and Dvali(ADD) model and Randall-Sundrum (RS) model. The sensitivity to model parameters can be improved compared to the present LEP or Tevatron sensitivity., Comment: references added; 9 pages, 6 figures