45 research outputs found

    Particle-Antiparticle Mixing, epsilon_K, Delta Gamma_q, A_SL^q, A_CP(B_d -> psi K_S), A_CP(B_s -> psi phi) and B -> X_{s,d} gamma in the Littlest Higgs Model with T-Parity

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    We calculate a number of observables related to particle-antiparticle mixing in the Littlest Higgs model with T-parity (LHT). The resulting effective Hamiltonian for Delta F=2 transitions agrees with the one of Hubisz et al., but our phenomenological analysis goes far beyond the one of these authors. In particular, we point out that the presence of mirror fermions with new flavour and CP-violating interactions allows to remove the possible Standard Model (SM) discrepancy between the CP asymmetry S_{psi K_S} and large values of |V_ub| and to obtain for the mass difference Delta M_s < (Delta M_s)_SM as suggested by the recent result by the CDF collaboration. We also identify a scenario in which simultaneously significant enhancements of the CP asymmetries S_{phi psi} and A_SL^q relative to the SM are possible, while satisfying all existing constraints, in particular from the B -> X_s gamma decay and A_CP(B -> X_s gamma) that are presented in the LHT model here for the first time. In another scenario the second, non-SM, value for the angle gamma=-(109+-6) from tree level decays, although unlikely, can be made consistent with all existing data with the help of mirror fermions. We present a number of correlations between the observables in question and study the implications of our results for the mass spectrum and the weak mixing matrix of mirror fermions. In the most interesting scenarios, the latter one turns out to have a hierarchical structure that differs significantly from the CKM one.Comment: 51 pages, 20 figures, 1 table. Extended discussion of the phases in the new mixing matrix V_Hd, some references added or updated, conclusions unchanged. Final version published in JHE

    Resonant decay of flat directions

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    We study preheating, i.e., non-perturbative resonant decay, of flat direction fields, concentrating on MSSM flat directions and the right handed sneutrino. The difference between inflaton preheating and flaton preheating, is that the potential is more constraint in the latter case. The effects of a complex driving field, quartic couplings in the potential, and the presence of a thermal bath are important and cannot be neglected. Preheating of MSSM flat directions is typically delayed due to out-of-phase oscillations of the real and imaginary components and may be preceded by perturbative decay or QQ-ball formation. Particle production due to the violation of adiabaticity is expected to be inefficient due to back reaction effects. For a small initial sneutrino VEV, ≲mN/h \lesssim m_N/h with mNm_N the mass of the right handed sneutrino and hh a yakawa coupling, there are tachyonic instabilities. The DD-term quartic couplings do not generate an effective mass for the tachyonic modes, making it an efficient decay channel. It is unclear how thermal scattering affects the resonance.Comment: 20 pages, 4 figure

    Localization and broadband follow-up of the gravitational-wave transient GW150914

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    A gravitational-wave (GW) transient was identified in data recorded by the Advanced Laser Interferometer Gravitational-wave Observatory (LIGO) detectors on 2015 September 14. The event, initially designated G184098 and later given the name GW150914, is described in detail elsewhere. By prior arrangement, preliminary estimates of the time, significance, and sky location of the event were shared with 63 teams of observers covering radio, optical, near-infrared, X-ray, and gamma-ray wavelengths with ground- and space-based facilities. In this Letter we describe the low-latency analysis of the GW data and present the sky localization of the first observed compact binary merger. We summarize the follow-up observations reported by 25 teams via private Gamma-ray Coordinates Network circulars, giving an overview of the participating facilities, the GW sky localization coverage, the timeline, and depth of the observations. As this event turned out to be a binary black hole merger, there is little expectation of a detectable electromagnetic (EM) signature. Nevertheless, this first broadband campaign to search for a counterpart of an Advanced LIGO source represents a milestone and highlights the broad capabilities of the transient astronomy community and the observing strategies that have been developed to pursue neutron star binary merger events. Detailed investigations of the EM data and results of the EM follow-up campaign are being disseminated in papers by the individual teams

    Women, sport and new media technologies:Derby grrrls online

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    Sport has long been viewed as a public ‘good’ — a space for the creation and enactment of the ‘good, healthy citizen’. Yet this public ‘good’ has also been gendered masculine: competitive, public and ‘tough’, with women’s participation historically marginal to men’s. In Australia in recent years, the participation of women and girls has fluctuated, with decline or stagnation in more traditional organised sports (netball, basketball) and growth in other areas, such as roller derby and football. However, women’s sports are still largely invisible in the popular sport media. In this chapter we focus on roller derby as one particular women’s sport that has undergone a global revival, mobilised through ‘new’ youth-oriented media forms. We examine four diverse websites that form part of the ‘social web’ of derby: two official league sites, a blog and a Facebook group. The reinvention of roller derby is intimately connected to the alternative mediated spaces made possible by the social web. Roller derby players and organisers have used online spaces for various ends: to promote the sport community, to make visible the relations of power between those involved, to create and maintain boundaries of inclusion and exclusion within the sport, and to express ‘creative’ aspects of identity. This chapter provides examples of the strategies and tactics used to establish and maintain roller derby as a ‘women’s only’ sport and some of the challenges and possibilities inherent in this highly mediated space.No Full Tex

    Building Reasearch Advisory Service survey report on polyester reinforced felt roof coverings Report of site inspections to determine the condition of polyester reinforced felt roof coverings more than seven years old

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    Report also known as BRE--106/2/1SIGLEAvailable from British Library Document Supply Centre- DSC:4669.4755(BFRC-Job--86/19) / BLDSC - British Library Document Supply CentreGBUnited Kingdo

    Building Reasearch Advisory Service survey report on polyester reinforced felt roof coverings Report of site inspections to determine the condition of polyester reinforced felt roof coverings more than seven years old

    No full text
    Report also known as BRE--106/2/1SIGLEAvailable from British Library Document Supply Centre- DSC:4669.4755(BFRC-Job--86/19) / BLDSC - British Library Document Supply CentreGBUnited Kingdo
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