New physics signatures at a Linear Collider: model-independent analysis from `conventional' polarized observables

We discuss four-fermion contact-interaction searches in the processes e^+e^-\to\mu^+\mu^-, c{\bar c} and b{\bar b} at a future e^+e^- Linear Collider with c.m. energy \sqrt{s}=0.5 TeV and with both beams longitudinally polarized. Our analysis is based on the measurements of familiar polarized observables such as the total cross section and the forward-backward/left-right asymmetries, and accounts for the general set of contact interaction couplings as independent, non-zero, parameters thus avoiding simplifying, model-dependent, assumptions. We derive the corresponding model-independent constraints on the above-mentioned coupling constants, and evaluate the corresponding reach at the Linear Collider, emphasizing the role of beam polarization. We compare the results with a model-dependent procedure where only one coupling is varied at a time.Comment: 13 pages, including 3 figure

Eliminating the low-mass axigluon window

Using recent collider data, especially on the hadronic width the Z0, we exclude axigluons in the currently allowed low-mass window, namely axigluons in the mass range 50 GeV < M_A < 120 GeV. Combined with hadron collider data from di-jet production, axigluons with masses below roughly 1 TeV are now completely excluded.Comment: 8 pages, no figures, LaTe

Energy Conservation Constraints on Multiplicity Correlations in QCD Jets

We compute analytically the effects of energy conservation on the self-similar structure of parton correlations in QCD jets. The calculations are performed both in the constant and running coupling cases. It is shown that the corrections are phenomenologically sizeable. On a theoretical ground, energy conservation constraints preserve the scaling properties of correlations in QCD jets beyond the leading log approximation.Comment: 11 pages, latex, 5 figures, .tar.gz version avaliable on ftp://www.inln.unice.fr

Vector boson pair production in e-e- collisions with polarized beams

The $W$-boson pair production in $e^-e^-$ collisions with polarized beams is investigated. The helicity amplitudes are derived for general couplings and the conditions for a good high-energy behaviour of the cross-section are given. The results are applied to the heavy vector boson production in the context of the left-right symmetric model. The Ward identities and the equivalence theorem are also discussed.Comment: 17 pages+ 8 figures(uuencoded compressed ps-file appended), HU-SEFT R 1994-09 (the original version of the file was unreproducable in some computers

Analysis of MERCATOR data Part I: variable B stars

We re-classified 31 variable B stars which were observed more than 50 times in the Geneva photometric system with the P7 photometer attached to the MERCATOR telescope (La Palma) during its first 3 years of scientific observations. HD89688 is a possible beta Cephei/slowly pulsating B star hybrid and the main mode of the COROT target HD180642 shows non-linear effects. The Maia candidates are re-classified as either ellipsoidal variables or spotted stars. Although the mode identification is still ongoing, all the well-identified modes so far have a degree l = 0, 1 or 2.Comment: 4 pages, 3 figures. To appear in: Proceedings of JENAM 2005 'Distant worlds', Communications in Asteroseismolog

Who violates expectations when? How firms’ growth and dividend reputations affect investors’ reactions to acquisitions

Research summary: We investigate the role of a firm’s dividend and growth reputations in shaping investors’ interpretations of acquisitions as a negative or positive expectation violation. While our findings reveal that both an acquiring firm’s dividend and growth reputations trigger positive investor reactions, they also show that investors react negatively to an acquisition of a target firm with a strong growth reputation when the acquiring firm has a strong dividend reputation. We also find that investors are inclined to give managers “the benefit of the doubt” to the extent that an acquiring firm strategically frames an acquisition announcement in such a way that it provides assurance to investors that the acquisition is meant to exceed investors’ expectations about shareholder value creation. Managerial summary: We study why investors respond to some acquisitions positively and others negatively. We find that the way acquiring and target firms have created shareholder value in the past, and the information conveyed in the acquisition announcements are important determinants of investors’ differential reactions to acquisitions. Our findings show that while investors generally react positively to acquisitions by firms known for creating value either through dividends or growth, their reactions become negative when a firm known for value creation through dividends acquires a target known for value creation through growth. We further find that managers can favorably influence investor reactions by making it salient in the acquisition announcement how the acquisition is intended to exceed investors’ value creation expectations from the acquiring firm

Selectron Studies at e-e- and e+e- Colliders

Selectrons may be studied in both e-e- and e+e- collisions at future linear colliders. Relative to e+e-, the e-e- mode benefits from negligible backgrounds and \beta threshold behavior for identical selectron pair production, but suffers from luminosity degradation and increased initial state radiation and beamstrahlung. We include all of these effects and compare the potential for selectron mass measurements in the two modes. The virtues of the e-e- collider far outweigh its disadvantages. In particular, the selectron mass may be measured to 100 MeV with a total integrated luminosity of 1 fb^-1, while more than 100 fb^-1 is required in e+e- collisions for similar precision.Comment: 16 pages, 11 figure

Charginos and Neutralinos Production at 3-3-1 Supersymmetric Model in e−e−e^-e^- Scattering

The goal of this article is to derive the Feynman rules involving charginos, neutralinos, double charged gauge bosons and sleptons in a 3-3-1 supersymmetric model. Using these Feynman rules we will calculate the production of a double charged chargino with a neutralino and also the production of a pair of single charged charginos, both in an electron- electron $e^-e^-$ process.Comment: 18 pages, 8 figures, 2 table