arXiv subjects

M. B. Magro

Publications and source records attributed to M. B. Magro.

27 records · Page 2Linked to original sources

arXiv1998

Signal and Backgrounds for the Single Production of Scalar and Vector Leptoquarks at the LHC

We perform a detailed analysis of the potentiality of the CERN Large Hadron Collider to study the single production of leptoquarks via $pp \to e^\pm q\to$ leptoquark $\to e^\pm q$, with $e^\pm$ generated by the splitting of photons radiated by the protons. Working with the most general $SU(2)_L \otimes U(1)_Y$ invariant effective lagrangian for scalar and vector leptoquarks, we analyze in detail the leptoquark signals and backgrounds that lead to a final state containing an $e^\pm$ and a hard jet with approximately balanced transverse momenta. Our results indicate that the LHC will be able to discover leptoquarks with masses up to 2--3 TeV, depending on their type, for Yukawa couplings of the order of the electromagnetic one.

hep-ph↗

arXiv1997

Gluino Cascade Decays With Broken R--Parity

We study the pattern of gluino cascade decays in a class of supersymmetric models where R-parity is spontaneously broken. The multi-lepton and same-sign dilepton rates in these models are compared with those of the Minimal Supersymmetric Standard Model. We show that these rates can be substantially enhanced in models with broken R-parity.

hep-ph↗

arXiv1996

Signatures of Spontaneous Breaking of R-Parity in Gluino Cascade Decays at LHC

We study the pattern of gluino cascade decays in a class of supersymmetric models where R-parity is spontaneously broken. We give a detailed discussion of the R-parity violating decays of the lightest neutralino, the second lightest neutralino and the lightest chargino. The multi-lepton and same-sign dilepton signal rates expected in these models are compared with those predicted in the Minimal Supersymmetric Standard Model. We show that these rates can be substantially enhanced in broken R-parity models.

hep-ph↗

arXiv1996

New Signatures for a Light Stop at LEP2 in SUSY Models with Spontaneously Broken R-Parity

In a class of supersymmetric models with R-parity breaking the lightest stop can have new decay modes into third generation fermions, $\tilde{t}_1 \rightarrow b + τ$. We show that this decay may be dominant or at least comparable to the ordinary R-parity conserving mode $\tilde{t}_1 \rightarrow c + \tildeχ_1^0$, where $\tildeχ_1^0$ denotes the lightest neutralino. The new R-parity violating decay mode could provide new signatures for stop production at LEP.

hep-ph↗

arXiv1996

LEP Sensitivities to Spontaneous R-Parity Violating Signals

We illustrate the sensitivities of LEP experiments to leptonic signals associated to models where supersymmetry (SUSY) is realized with spontaneous breaking of R-parity. We focus on missing transverse momentum plus acoplanar muon events arising from lightest neutralino single production $χν$ as well as pair production $χχ$, followed by $χ$ decays, where $χ$ denotes the lightest neutralino. We show that the integrated luminosity achieved at LEP already starts probing the basic parameters of the theory. We discuss the significance of these constraints for the simplest spontaneous R-parity breaking models and their relevance for future searches of SUSY particles.

hep-ph↗

arXiv1995

Anomalous g^5_z coupling at $γγ$ colliders

We study the constraints on the anomalous coupling $g^Z_5$ that can be obtained from the analysis of the reaction $γγ\rightarrow W^+ W^- Z$ at future linear $e^+e^-$ colliders. We find out that a $0.5$ ($1$) TeV $e^+e^-$ collider operating in the $γγ$ mode can probe values of $g_5^Z$ of the order of $0.15$ ($4.5 \times 10^{-2}$) for an integrated luminosity of $10$ fb$^{-1}$. This shows that the ability to search for this anomalous interaction of the $γγ$ mode is better than the one of the usual $e^+e^-$ mode, and it is similar to the ability of the $eγ$ mode.

hep-ph↗

arXiv1995

Quartic Anomalous Couplings in $γγ$ Colliders

We study the constraints on the vertices $W^+W^- Zγ$, $W^+W^-γγ$, and $ZZγγ$ that can be obtained from triple-gauge-boson production at the next generation of linear $e^+e^-$ colliders operating in the $γγ$ mode. We analyze the processes $γγ\to W^+W^-V$ ($V=Z$, or $γ$) and show that these reactions increase the potential of $e^+e^-$ machines to search for anomalous four-gauge-boson interactions.

hep-ph↗

arXiv1993

Triple Vector Boson Processes in $γγ$ Colliders

We study the production of three gauge bosons at the next generation of linear $e^+e^-$ colliders operating in the $γγ$ mode. The processes $γγ\rightarrow W^+W^-V$ ($V=Z^0$, or $γ$) can provide direct information about the quartic gauge-boson couplings. We analyze the total cross section as well as several dynamical distributions of the final state particles including the effect of kinematical cuts. We find out that a linear $e^+e^-$ machine operating in the $γγ$ mode will produce 5--10 times more three-gauge-boson states compared to the standard $e^+e^-$ mode at high energies.

hep-ph↗

arXiv1993

Searching for Leptoquarks in electron-photon Collisions

We study the production of composite scalar leptoquarks in $eγ$ colliders, and we show that an $e^+e^-$ machine operating in its $eγ$ mode is the best way to look for these particles in $e^+e^-$ collisions, due to the hadronic content of the photon.

hep-ph↗