29 research outputs found

    Pair Production of Fourth Family Charged Sleptons at e+ee^{+}e^{-} Colliders

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    We study the pair production of l~4\tilde{l}_{4}, which is the supersymmetric partner of the fourth family charged lepton, at the e+ee^{+}e^{-} colliders. It is shown that the investigation of this process at ILC/CLIC will give opportunity to differentiate the MSSM with three and four families.Comment: 6 pages, 2 figure

    SM with four generations: Selected implications for rare B and K decays

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    We extend our recent work and study implications of the Standard Model with four generations (SM4) for rare B and K decays. We again take seriously the several 2-3 σ\sigma anomalies seen in B, BsB_s decays and interpret them in the context of this simple extension of the SM. SM4 is also of course of considerable interest for its potential relevance to dynamical electroweak symmetry breaking and to baryogenesis. Using experimental information from processes such as BXsγB \to X_s \gamma, BdB_d and BsB_s mixings, indirect CP-violation from KLππK_L \to \pi \pi etc along with oblique corrections, we constrain the relevant parameter space of the SM4, and find mtm_{t'} of about 400-600 GeV with a mixing angle VtbVts| V_{t'b}^*V_{t's}| in the range of about (0.05 to 1.4)×102\times 10^{-2} and with an appreciable CP-odd associated phase, are favored by the current data. Given the unique role of the CP asymmetry in BsψϕB_s \to \psi \phi due to its gold-plated nature, correlation of that with many other interesting observables, including the semileptonic asymmetry (ASLA_{SL}) are studied in SM4. We also identify several processes, such as BXsννˉB \to X_s \nu \bar\nu, KLπ0ννˉK_L \to \pi^0 \nu \bar \nu etc, that are significantly different in SM4 from the SM. Experimentally the very distinctive process Bsμ+μB_s\to \mu^+\mu^- is also discussed; the branching ratio can be larger or smaller than in SM, (3.24.2)×109(3.2 \to 4.2)\times 10^{-9}, by a factor of O(3){\cal{O}}(3).Comment: v2: 49 pages, 20 eps figures, Corrected some typos, added few references and minor changes with regard to direct CP in K pi. Also some added information to facilitate direct comparison with Buras et al, arXiv:1002.2126

    Analysis of \Lambda_b \rar \Lambda \ell^+ \ell^- transition in SM4 using form factors from Full QCD

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    Using the responsible form factors calculated via full QCD, we analyze the ΛbΛ+\Lambda_{b}\rightarrow \Lambda \ell^{+}\ell^{-} transition in the standard model containing fourth generation quarks (SM4). We discuss effects of the presence of tt' fourth family quark on related observables like branching ratio, forward-backward asymmetry, baryon polarization as well as double lepton polarization asymmetries. We also compare our results with those obtained in the SM as well as with predictions of the SM4 but using form factors calculated within heavy quark effective theory. The obtained results on branching ratio indicate that the ΛbΛ+\Lambda_{b}\rightarrow \Lambda \ell^{+}\ell^{-} transition is more probable in full QCD comparing to the heavy quark effective theory. It is also shown that the results on all considered observables in SM4 deviate considerably from the SM predictions when mt400GeVm_{t'}\geq 400 GeV.Comment: 22 Pages and 21 Figure

    Search for a heavy bottom-like quark in pp collisions at √s =7 TeV

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    This is the Pre-Print version of the Article. The official published version of the paper can be accessed from the link below - Copyright @ 2011 Elsevier.A search for pair-produced bottom-like quarks in pp collisions at sqrt(s) = 7 TeV is conducted with the CMS experiment at the LHC. The decay b' to tW is considered in this search. The b' b'-bar to tW^- t-bar W^+ process can be identified by the distinctive signature of trileptons and same-sign dileptons. With a data sample corresponding to an integrated luminosity of 34 inverse picobarns, no excess above the standard model background predictions is observed and a b' quark with a mass between 255 and 361 GeV/c^2 is excluded at the 95% confidence level.This work is supported by the FMSR (Austria); FNRS and FWO (Belgium); CNPq, CAPES, FAPERJ, and FAPESP (Brazil); MES (Bulgaria); CERN; CAS, MoST, and NSFC (China); COLCIENCIAS (Colombia); MSES (Croatia); RPF (Cyprus); Academy of Sciences and NICPB (Estonia); Academy of Finland, ME, and HIP (Finland); CEA and CNRS/IN2P3 (France); BMBF, DFG, and HGF (Germany); GSRT (Greece); OTKA and NKTH (Hungary); DAE and DST (India); IPM (Iran); SFI (Ireland); INFN (Italy); NRF and WCU (Korea); LAS (Lithuania); CINVESTAV, CONACYT, SEP, and UASLP-FAI (Mexico); PAEC (Pakistan); SCSR (Poland); FCT (Portugal); JINR (Armenia, Belarus, Georgia, Ukraine, Uzbekistan); MST and MAE (Russia); MSTD (Serbia); MICINN and CPAN (Spain); Swiss Funding Agencies (Switzerland); NSC (Taipei); TUBITAK and TAEK (Turkey); STFC (United Kingdom); DOE and NSF (USA)

    Observation of gravitational waves from the coalescence of a 2.5−4.5 M⊙ compact object and a neutron star

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    Ultralight vector dark matter search using data from the KAGRA O3GK run

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    Among the various candidates for dark matter (DM), ultralight vector DM can be probed by laser interferometric gravitational wave detectors through the measurement of oscillating length changes in the arm cavities. In this context, KAGRA has a unique feature due to differing compositions of its mirrors, enhancing the signal of vector DM in the length change in the auxiliary channels. Here we present the result of a search for U(1)B−L gauge boson DM using the KAGRA data from auxiliary length channels during the first joint observation run together with GEO600. By applying our search pipeline, which takes into account the stochastic nature of ultralight DM, upper bounds on the coupling strength between the U(1)B−L gauge boson and ordinary matter are obtained for a range of DM masses. While our constraints are less stringent than those derived from previous experiments, this study demonstrates the applicability of our method to the lower-mass vector DM search, which is made difficult in this measurement by the short observation time compared to the auto-correlation time scale of DM

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    Not AvailableThe study was conducted by supplementing cupric chloride dihydrate to modulate the estradiol synthesis in granulosa cells with a hypothesis of possible use of copper to potentiate or partially replace the hormones for estrus induction / estrus synchronization in future studies. In present study copper at three doses (0.1, 0.5 and 1 mM level in culture medium) were tested to deserve see their effects on in vitro granulosa cell survival, estradiol synthesis and their associated genes of ovarian granulosa cells of goat.There was no effect of copper on the ovarian granulosa cell survival rate. There was a considerable increase in the estradiol level per ml culture medium basis by 6th day of in vitro culture with the second dose of copper i.e. 0.5 mM, but the increase was non-significant (P>0.05). There was no significant effect of copper on estradiol synthesis when expressed on per 30000 cell basis. Effect of copper (0.1 mM and 0.5 mM) on the mRNA expression of genes of aromatase (CYP19A1) and cyclin D2 (CCND2) was estimated. Copper had significantly (P<0.05) increased the mRNA expression of CCND2 and CYP19A1in ovarian granulosa cells with only one of the two doses tested i.e. 0.5 mM. Hence, copper can be considered as a potential mineral to supplement along with hormones in estrus induction or estrus synchronization protocols to minimize the use of hormones.ICAR-NIAN
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