arXiv subjects
Publications and source records attributed to Jan Kalinowski.
Reconstruction of the fundamental supersymmetric theory and its breaking mechanism will require high-precision tools. Here a brief introduction to SPA, the Supersymmetry Parameter Analysis (SPA) Convention and Project, is presented which is based on a consistent set of conventions and input parameters.
This report summarizes the progress in SUSY studies performed since the last International Linear Collider Workshop in Paris (LCWS04).
Establishing CP violation in B0 (bar{B0}) --> l+ l- decays requires a measurement of polarization of the final lepton pair, or a precise determination of the B0 --> l+ l- and bar{B0} --> l+ l- rates. We first argue that if the amplitudes of these decays are dominated by the scalar and pseudoscalar Higgs penguin diagrams, as happens e.g. in supersymmetry with large tan(beta), the CP asymmetries depend practically on only one CP violating phase. This phase can be large, of the order of the CKM phase, leading to large CP asymmetries in the tau+ tau- decay channel of B0_d (bar{B0}_d) mesons, potentially measurable in BELLE or BABAR experiments. Secondly, we show that the existing TAUOLA tau-lepton decay library supplemented by its universal interface can efficiently be used to search for B0 (bar{B0}) --> tau+ tau- decays, and to investigate how the CP asymmetry is reflected in realistic experimental observables.
A future linear e+e- collider with a clean environment, tunable collision energy, high luminosity, polarized incoming beams, and additional e-e-, e-gamma and gamma-gamma modes, will offer precision tools to explore new physics. Here we summarize three papers submitted to the ICHEP04 conference in which polarized e+e- and gamma-gamma beams are exploited to search for CP violation, and universal extra dimensions (UED).
This report summarizes the progress in SUSY studies performed during the Extended ECFA/DESY Workshop since the TESLA TDR. Based on accurate future measurements of masses of SUSY particles and the determination of the couplings and mixing properties of sfermions and gauginos, we discuss how the low-energy Lagrangian parameters can be determined. In a bottom-up approach, by extrapolating to higher energies, we demonstrate how model assumptions on SUSY breaking can be tested. To this end precise knowledge of the SUSY spectrum and the soft SUSY breaking parameters is necessary to reveal the underlying supersymmetric theory.
Supersymmetric particles can be produced copiously at future colliders. From the high-precision data taken at e+e- linear colliders, TESLA in particular, and combined with results from LHC, and CLIC later, the low-energy parameters of the supersymmetric model can be determined. Evolving the parameters from the low-energy scale to the high-scale by means of renormalization group techniques the fundamental supersymmetry parameters at the high scale, GUT or Planck, can be reconstructed to reveal the origin of supersymmetry breaking.
In supersymmetric extensions of the Standard Model, the lepton flavour violation (LFV) is closely related to the structure of slepton masses and mixing. Allowing for the most general flavour structure of the slepton sector, consistent with the experimental limits on rare lepton decays, large and distinct signals of LFV at future colliders can be expected. A case study of mixing of second and third generation of sleptons at an e+e- collider is presented and compared to that of tau to mu+gamma rare decay.
It is shown how the fundamental gaugino and higgsino parameters of the chargino and neutralino system in the MSSM can completely be determined in high--precision experiments at e+e- linear colliders even if in their initial phase only the light charginos $\tildeχ^\pm_1$ and the light neutralinos $\tildeχ^0_1$ and $\tildeχ^0_2$ are kinematically accessible.
Consecutively to the chargino system, $\tilde{chi}^pm$, in which the SU(2) gaugino parameter $M_2$, the higgsino mass parameter $μ$ and $\tanβ$ can be determined, the remaining fundamental supersymmetry parameter, the U(1) gaugino mass $M_1$ can be analysed in the neutralino system, $\tildeχ^0$, including its modulus and phase in CP--noninvariant theories. First experimental hints on CP violation can be seen in the threshold behaviour of neutralino production.
The chargino pair production processes at $e^+e^-$ collisions are explored to reconstruct the fundamental SUSY parameters: the SU(2) gaugino parameter $M_2$, the higgsino mass parameter $μ$ and $\tanβ$. Both CP-conserving and CP-violating SUSY sectors are discussed.
In a general two-Higgs-doublet model with CP violation in the Higgs sector, the three neutral physical Higgs bosons have no definite CP properties. A new sum rule relating Yukawa and Higgs-Z couplings implies that a neutral Higgs boson cannot escape detection at an e^+e^- collider if it is kinematically accessible in Z+Higgs, $b\bar b+$Higgs and $t\bar t+$Higgs production, irrespective of the mixing angles and the masses of the other neutral Higgs bosons. The implications of the sum rules for Higgs discovery at the Tevatron and LHC are briefly mentioned.
A procedure to determine the chargino mixing angles and, subsequently, the fundamental SUSY parameters M2, mu and tan(beta) by measurements of the total cross section and the spin correlations in e+e- annihilation to chi1^+ chi1^- chargino pairs is discussed.
The physics potential of discovering and exploring supersymmetry at future e^+e^- linear colliders is reviewed. Such colliders are planned to start to operate at a center-of-mass energy of 500 GeV to 800 GeV, with a final energy of about 2 TeV expected. They are ideal facilities for the discovery of supersymmetric particles. High precision measurements of their properties and interactions will help to uncover the mechanism of supersymmetry breaking and will allow for tests of grand unification scenarios.
We investigate the sensitivity of future linear collider experiments to CP violating $WWγ$ couplings in the process $e^{+}e^{-} \to ν\barνγ$. We consider several sets of machine parameters: centre of mass energies $\sqrt{s}$ = 350, 500 and 800 GeV and operating at different luminosities. From an analysis of the differential cross-section the following 95% C.L. limits $|\tildeκ_γ| < 0.18$, $|\tildeλ_γ| < 0.069$ are estimated to be obtained at a future 500 GeV LC with an integrated luminosity of $125 \fb^{-1}$, a great improvement as compared to the LEP2 reach, where a senstitivity of order 2 for both couplings is found.
In R-parity violating SUSY models sleptons can be produced singly in e+e- and qqbar collisions. The formation of slepton resonances at LEP2 or Tevatron at current energies is an exciting possibility. Existing LEP2 and Tevatron data can be exploited to look for sleptons and, if unsuccessful, to derive bounds on the Yukawa couplings of sleptons to quark and lepton pairs.
In supersymmetric theories with R-parity breaking, sleptons could be produced singly in $e^+e^-$ collisions at LEP2 and in $q\bar{q}$ annihilation at the Tevatron through interactions in which two quark or two lepton fields are coupled to a slepton field. At LEP they could manifest themselves in Bhabha scattering, and in the annihilation to $μ^+μ^-$, \taus, and $q\bar{q}$ pairs. The formation of sneutrinos, $e^+e^-\ra \tiν$, and their signals for a mass within the reach of this machine, is an exciting speculation which can be investigated in the coming LEP2 runs with energies close to $\sqrt{s}=200$ GeV. At the Tevatron the sleptons can be searched for as resonances in $p\bar{p}\to \tildeν \to \ell^+\ell^-$ and $\tilde{\ell}\to \ellν$ final states. Existing LEP2 and Tevatron data can be exploited to derive bounds on the Yukawa couplings of sleptons to quark and lepton pairs.
If the sneutrino mass is below the chargino mass, the dominant decay mode of the lightest chargino is via a two-body decay channel $χ^{\pm}_1 \ra \tildeν + l^{\pm}$. Sneutrinos are invisible in $R$-parity conserving supersymmetric models and, if the mass gap $m(χ^{\pm}_1)-m(\tildeν)$ is sufficiently small, the soft decay lepton may escape detection leading to invisible chargino decays. This ``blind spot'' of the supersymmetry parameter space would jeopardize the chargino search at LEP2. We point out that such a scenario can be tested by searching for single $W$ events in $e^+e^- \ra W^+W^-$, with one $W$ boson decaying to visible leptons or quark jets, and the second $W$ boson decaying to invisible charginos and neutralinos.
We perform a detailed analysis of the processes $e^+e^- \rightarrow \barν νγ$ and $\barνν\bar{q}q$ at future linear $e^+e^-$ colliders and assess their sensitivity to anomalous gauge boson couplings. We consider center of mass energies $\sqrt{s}=$ 350, 500 and 800 GeV. We demonstrate that significant improvements can be obtained if the phase space information for the cross sections is used maximally. At 800 GeV the parameters $Δκ_γ$ and $λ_γ$ can be constrained, at 95\% CL, to about 0.02 and 0.01, while the parameters $Δκ_Z$, $λ_Z$ and $Δg_1^Z$ can be probed down to about 0.009, 0.002 and 0.004 respectively. The precision of these measurements is likely to be limited by statistical errors at anticipated luminosities at these energies.