129 research outputs found

    On Direct Verification of Warped Hierarchy-and-Flavor Models

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    We consider direct experimental verification of warped models, based on the Randall-Sundrum (RS) scenario, that explain gauge and flavor hierarchies, assuming that the gauge fields and fermions of the Standard Model (SM) propagate in the 5D bulk. Most studies have focused on the bosonic Kaluza Klein (KK) signatures and indicate that discovering gauge KK modes is likely possible, yet challenging, while graviton KK modes are unlikely to be accessible at the LHC, even with a luminosity upgrade. We show that direct evidence for bulk SM fermions, {\it i.e.} their KK modes, is likely also beyond the reach of a luminosity-upgraded LHC. Thus, neither the spin-2 KK graviton, the most distinct RS signal, nor the KK SM fermions, direct evidence for bulk flavor, seem to be within the reach of the LHC. We then consider hadron colliders with s=\sqrt{s} = 21, 28, and 60 TeV. We find that discovering the first KK modes of SM fermions and the graviton typically requires the Next Hadron Collider (NHC) with s60\sqrt{s} \approx 60 TeV and O(1){\cal O}(1) ab1^{-1} of integrated luminosity. If the LHC yields hints of these warped models, establishing that Nature is described by them, or their 4D CFT duals, requires an NHC-class machine in the post-LHC experimental program.Comment: Revtex4, 21 pages, 11 figure

    Neutrinos in a left-right model with a horizontal symmetry

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    We analyze the lepton sector of a Left-Right Model based on the gauge group SU(2)_L x SU(2)_R x U(1), concentrating mainly on neutrino properties. Using the seesaw mechanism and a horizontal symmetry, we keep the right-handed symmetry breaking scale relatively low, while simultaneously satisfying phenomenological constraints on the light neutrino masses. We take the right-handed scale to be of order 10's of TeV and perform a full numerical analysis of the model's parameter space, subject to experimental constraints on neutrino masses and mixings. The numerical procedure yields results for the right-handed neutrino masses and mixings and the various CP-violating phases. We also discuss phenomenological applications of the model to neutrinoless double beta decay, lepton-flavor-violating decays (including decays such as \tau \to 3\mu) and leptogenesis.Comment: 26 pages, 4 figure

    Underwater Navigation using Pseudolite

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    Using pseudolite or pseudo satellite, a proven technology for ground and space applications for the augmentation of GPS, is proposed for underwater navigation. Global positioning systems (GPS) like positioning for underwater system, needs minimum of four pseudolite-ranging signals for pseudo-range and accumulated delta range measurements. Using four such measurements and using the models of underwater attenuation and delays, the navigation solution can be found. However, for application where the one-way ranging does not give good accuracy, alternative algorithms based upon the bi-directional and self-difference ranging is proposed using selfcalibrated pseudolite array algorithm. The hardware configuration is proposed for pseudolite transceiver for making the self-calibrated array. The pseudolite array, fixed or moored under the sea, can give position fixing similar to GPS for underwater applications.Defence Science Journal, 2011, 61(4), pp.331-336, DOI:http://dx.doi.org/10.14429/dsj.61.108

    Modelling and Simulation of Pseudolite-based Navigation: A GPS-independent Radio Navigation System

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    The use of global positioning system (GPS) for precision guidance of weapons is being questioned due to its vulnerability of jamming and spoofing for non-military code users. In this paper a novel approach is proposed for guidance of weapons where use of GPS or other civilian Satellite-based navigation system is threatened. The proposed approach is modelled and simulated using SIMULINK for realistic trajectories and scenario. The results of simulation are validated with the actual GPS data

    B-factory Signals for a Warped Extra Dimension

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    We study predictions for B-physics in a class of models, recently introduced, with a non-supersymmetric warped extra dimension. In these models few (3\sim 3) TeV Kaluza-Klein masses are consistent with electroweak data due to bulk custodial symmetry. Furthermore, there is an analog of GIM mechanism which is violated by the heavy top quark (just as in SM) leading to striking signals at BB-factories:(i) New Physics (NP) contributions to ΔF=2\Delta F= 2 transitions are comparable to SM. This implies that, within this NP framework, the success of SM unitarity triangle fit is a ``coincidence'' Thus, clean extractions of unitarity angles via e.g. Bππ,ρπ,ρρ,DKB \to \pi \pi,\rho \pi, \rho \rho, DK are likely to be affected, in addition to O(1) deviation from SM prediction in BsB_s mixing. (ii) O(1) deviation from SM predictions for BXsl+lB \to X_s l^+ l^- in rate as well as in forward-backward and direct CP asymmetry. (iii) Large mixing-induced CP asymmetry in radiative B decays, wherein the SM unamibgously predicts very small asymmetries. Also with KK masses 3 TeV or less, and with anarchic Yukawa masses, contributions to electric dipole moments of the neutron are roughly 20 times larger than the current experimental bound so that this framework has a "CP problem".Comment: On further consideration, we found that our framework does have a "CP problem" in that though contributions to neutron's electric dipole moment from CKM-like phases vanish at the one-loop level, sizeable contributions are induced by Majorana-like phases. Last sentence of abstract is changed along with para #3 and 4 on page

    Extended Friedberg Lee hidden symmetries, quark masses and CP-violation with four generations

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    Motivated in part by the several observed anomalies involving CP asymmetries of B and B_s decays, we consider the Standard Model with a 4th sequential family (SM4) which seems to offer a rather simple resolution. We initially assume T-invariance by taking the up and down-quark 4x4 mass matrix to be real. Following Friedberg and Lee (FL), we then impose a "hidden" symmetry on the unobserved ("hidden") up and down-quark SU(2) states. The hidden symmetry for four generations ensures the existence of two zero-mass eigenstates, which we take to be the (u,c) and (d,s) states in the up and down-quark sectors, respectively. Then, we simultaneously break T-invariance and the hidden symmetry by introducing two phase factors in each sector. This breaking mechanism generates the small quark masses m_u, m_c and m_d, m_s which, along with the orientation of the hidden symmetry, determine the size of CP-violation in the SM4. For illustration we choose a specific physical picture for the hidden symmetry and the breaking mechanism that reproduces the observed quark masses, mixing angles and CP-violation, and at the same time allows us to further obtain very interesting relations/predictions for the mixing angles of t and t'. For example, with this choice we get V_{td} ~ (V_{cb}/V_{cd} - V_{ts}/V_{us}) + O(\lambda^2) and V_{t'b} ~ V_{t'd}x(V_{cb}/V_{cd}), V_{tb'} ~ V_{t'd}x(V_{ts}/V_{us}), implying that V_{t'd} > V_{t'b},V_{tb'}. We furthermore find that the Cabibbo angle is related to the orientation of the hidden symmetry and that the key CP-violating quantity of our model at high-energies, J_{SM4} = Im[V_{tb} V_{t'b}^* V_{t'b'} V_{tb'}^*], which is the high-energy analogue of the Jarlskog invariant of the SM, is proportional to the light-quark masses and the measured CKM angles.Comment: 19 page

    Two body decays of the bb-quark: Applications to direct CP violation, searches for electro-weak penguins and new physics

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    A systematic experimental search for two-body hadronic decays of the b-quark of the type b to quark + meson is proposed. These reactions have a well defined experimental signature and they should be theoretically cleaner compared to exclusive decays. Many modes have appreciable branching ratios and partial rate asymmetries may also be quite large (about 8-50%) in several of them. In a few cases electroweak penguins appear to be dominant and may be measurable. CP violating triple correlation asymmetries provide a clean test of the Standard Model.Comment: 12 pages 1 figure 1 tabl

    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

    Extracting information on CKM phases, electro-weak penguins and new physics from B --> VV decays

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    We derive constraints for BVVB\to VV modes ($V= vector meson) that allow aquantitative assessment of the contributions from electroweak penguins (EWP) and/or new physics. Interplay of direct CP with oscillation studies then leads to the extraction of the angles alpha and gamma, using B--> K* omega rho and B--> rho omega (phi) respectively, if by using our constraint equations it can be experimentally demonstrated that color-suppressed EWP are small.Comment: 12 pages, 0 figures; revised and expande

    Flavor Structure of Warped Extra Dimension Models

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    We recently showed, in hep-ph/0406101, that warped extra dimensional models with bulk custodial symmetry and few TeV KK masses lead to striking signals at BB-factories. In this paper, using a spurion analysis, we systematically study the flavor structure of models that belong to the above class. In particular we find that the profiles of the zero modes, which are similar in all these models, essentially control the underlying flavor structure. This implies that our results are robust and model independent in this class of models. We discuss in detail the origin of the signals in B-physics. We also briefly study other NP signatures that arise in rare K decays (KπννK \to \pi \nu \nu), in rare top decays [tcγ(Z,gluon)t \to c \gamma (Z, gluon)] and the possibilty of CP asymmetries in D0D^0 decays to CP eigenstates such as KSπ0K_S \pi^0 and others. Finally we demonstrate that with light KK masses, 3\sim3 TeV, the above class of models with anarchic 5D5D Yukawas has a ``CP problem'' since contributions to the neutron electric dipole moment are roughly 20 times larger than the current experimental bound. Using AdS/CFT correspondence, these extra-dimensional models are dual to a purely 4D strongly coupled conformal Higgs sector thus enhancing their appeal.Comment: 41 pages, 52 pages including appendice
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