56 research outputs found

    Compact boson stars in K field theories

    Full text link
    We study a scalar field theory with a non-standard kinetic term minimally coupled to gravity. We establish the existence of compact boson stars, that is, static solutions with compact support of the full system with self-gravitation taken into account. Concretely, there exist two types of solutions, namely compact balls on the one hand, and compact shells on the other hand. The compact balls have a naked singularity at the center. The inner boundary of the compact shells is singular, as well, but it is, at the same time, a Killing horizon. These singular, compact shells therefore resemble black holes.Comment: Latex, 45 pages, 25 figures, some references and comments adde

    Quasinormal modes from potentials surrounding the charged dilaton black hole

    Full text link
    We clarify the purely imaginary quasinormal frequencies of a massless scalar perturbation on the 3D charged-dilaton black holes. This case is quite interesting because the potential-step appears outside the event horizon similar to the case of the electromagnetic perturbations on the large Schwarzschild-AdS black holes. It turns out that the potential-step type provides the purely imaginary quasinormal frequencies, while the potential-barrier type gives the complex quasinormal modes.Comment: 19 pages, 8 figure

    Constraining the electric charges of some astronomical bodies in Reissner-Nordstrom spacetimes and generic r^-2-type power-law potentials from orbital motions

    Full text link
    We put model-independent, dynamical constraints on the net electric charge Q of some astronomical and astrophysical objects by assuming that their exterior spacetimes are described by the Reissner-Nordstroem metric, which induces an additional potential U_RN \propto Q^2 r^-2. Our results extend to other hypothetical power-law interactions inducing extra-potentials U_pert = r^-2 as well (abridged).Comment: LaTex2e, 16 pages, 3 figures, no tables, 128 references. Version matching the one at press in General Relativity and Gravitation (GRG). arXiv admin note: substantial text overlap with arXiv:1112.351

    Model-independent search for CP violation in D0→K−K+π−π+ and D0→π−π+π+π− decays

    Get PDF
    A search for CP violation in the phase-space structures of D0 and View the MathML source decays to the final states K−K+π−π+ and π−π+π+π− is presented. The search is carried out with a data set corresponding to an integrated luminosity of 1.0 fb−1 collected in 2011 by the LHCb experiment in pp collisions at a centre-of-mass energy of 7 TeV. For the K−K+π−π+ final state, the four-body phase space is divided into 32 bins, each bin with approximately 1800 decays. The p-value under the hypothesis of no CP violation is 9.1%, and in no bin is a CP asymmetry greater than 6.5% observed. The phase space of the π−π+π+π− final state is partitioned into 128 bins, each bin with approximately 2500 decays. The p-value under the hypothesis of no CP violation is 41%, and in no bin is a CP asymmetry greater than 5.5% observed. All results are consistent with the hypothesis of no CP violation at the current sensitivity

    Search for the lepton-flavor-violating decays Bs0→e±μ∓ and B0→e±μ∓

    Get PDF
    A search for the lepton-flavor-violating decays Bs0→e±μ∓ and B0→e±μ∓ is performed with a data sample, corresponding to an integrated luminosity of 1.0  fb-1 of pp collisions at √s=7  TeV, collected by the LHCb experiment. The observed number of Bs0→e±μ∓ and B0→e±μ∓ candidates is consistent with background expectations. Upper limits on the branching fractions of both decays are determined to be B(Bs0→e±μ∓)101  TeV/c2 and MLQ(B0→e±μ∓)>126  TeV/c2 at 95% C.L., and are a factor of 2 higher than the previous bounds

    Branching fraction and CP asymmetry of the decays B+→K0Sπ+ and B+→K0SK+

    Get PDF
    An analysis of B+ → K0 Sπ+ and B+ → K0 S K+ decays is performed with the LHCb experiment. The pp collision data used correspond to integrated luminosities of 1 fb−1 and 2 fb−1 collected at centre-ofmass energies of √ s = 7 TeV and √ s = 8 TeV, respectively. The ratio of branching fractions and the direct CP asymmetries are measured to be B(B+ → K0 S K+ )/B(B+ → K0 Sπ+ ) = 0.064 ± 0.009 (stat.) ± 0.004 (syst.), ACP(B+ → K0 Sπ+ ) = −0.022 ± 0.025 (stat.) ± 0.010 (syst.) and ACP(B+ → K0 S K+ ) = −0.21 ± 0.14 (stat.) ± 0.01 (syst.). The data sample taken at √ s = 7 TeV is used to search for B+ c → K0 S K+ decays and results in the upper limit ( fc · B(B+ c → K0 S K+ ))/( fu · B(B+ → K0 Sπ+ )) < 5.8 × 10−2 at 90% confidence level, where fc and fu denote the hadronisation fractions of a ¯b quark into a B+ c or a B+ meson, respectively

    A study of CP violation in B-+/- -> DK +/- and B-+/- -> D pi(+/-) decays with D -> (KSK +/-)-K-0 pi(-/+) final states

    Get PDF
    A first study of CP violation in the decay modes B-+/- -> [(KSK +/-)-K-0 pi(-/+)](D)h(+/-) and B-+/- -> [(KSK +/-)-K-0 pi(-/+)](D)h(+/-), where h labels a K or pi meson and D labels a D-0 or (D) over bar (0) meson, is performed. The analysis uses the LHCb data set collected in pp collisions, corresponding to an integrated luminosity of 3 fb(-1). The analysis is sensitive to the CP-violating CKM phase gamma through seven observables: one charge asymmetry in each of the four modes and three ratios of the charge-integrated yields. The results are consistent with measurements of gamma using other decay modes

    Measurement of ϒ production in pp collisions at √s = 2.76 TeV

    Get PDF
    The production of ϒ(1S), ϒ(2S) and ϒ(3S) mesons decaying into the dimuon final state is studied with the LHCb detector using a data sample corresponding to an integrated luminosity of 3.3 pb−1 collected in proton–proton collisions at a centre-of-mass energy of √s = 2.76 TeV. The differential production cross-sections times dimuon branching fractions are measured as functions of the ϒ transverse momentum and rapidity, over the ranges pT &#60; 15 GeV/c and 2.0 &#60; y &#60; 4.5. The total cross-sections in this kinematic region, assuming unpolarised production, are measured to be σ (pp → ϒ(1S)X) × B ϒ(1S)→μ+μ− = 1.111 ± 0.043 ± 0.044 nb, σ (pp → ϒ(2S)X) × B ϒ(2S)→μ+μ− = 0.264 ± 0.023 ± 0.011 nb, σ (pp → ϒ(3S)X) × B ϒ(3S)→μ+μ− = 0.159 ± 0.020 ± 0.007 nb, where the first uncertainty is statistical and the second systematic

    Search for CP violation in D±KS0K±D^{\pm}\rightarrow K^0_{\mathrm{S}} K^{\pm} and Ds±KS0π±D^{\pm}_{s}\rightarrow K^0_{\mathrm{S}} π^{\pm} decays

    Get PDF
    A search for \CP violation in Cabibbo-suppressed D±KS0K±D^{\pm}\rightarrow K^0_{\mathrm{S}} K^{\pm} and Ds±KS0π±D^{\pm}_{s}\rightarrow K^0_{\mathrm{S}} \pi^{\pm} decays is performed using pppp collision data, corresponding to an integrated luminosity of 3~fb1^{-1}, recorded by the LHCb experiment. The individual CPCP-violating asymmetries are measured to be \begin{eqnarray*} \mathcal{A}_{CP}^{D^{\pm}\rightarrow K^0_{\mathrm{S}} K^{\pm}} & = & (+0.03 \pm 0.17 \pm 0.14) \% \mathcal{A}_{CP}^{D^{\pm}_{s}\rightarrow K^0_{\mathrm{S}} \pi^{\pm}} & = & (+0.38 \pm 0.46 \pm 0.17) \%, \end{eqnarray*} assuming that CPCP violation in the Cabibbo-favoured decays is negligible. A combination of the measured asymmetries for the four decay modes D(s)±KS0K±D^{\pm}_{(s)}\rightarrow K^0_{\mathrm{S}} K^{\pm} and D(s)±KS0π±D^{\pm}_{(s)}\rightarrow K^0_{\mathrm{S}} \pi^{\pm} gives the sum ACPD±KS0K±+ACPDs±KS0π±=(+0.41±0.49±0.26)%. \mathcal{A}_{CP}^{D^{\pm}\rightarrow K^0_{\mathrm{S}} K^{\pm}} + \mathcal{A}_{CP}^{D^{\pm}_{s}\rightarrow K^0_{\mathrm{S}} \pi^{\pm}} = (+0.41 \pm 0.49 \pm 0.26) \%. In all cases, the first uncertainties are statistical and the second systematic. The results represent the most precise measurements of these asymmetries to date and show no evidence for CP violation

    Higgs Boson Studies at the Tevatron

    Get PDF
    We combine searches by the CDF and D0 Collaborations for the standard model Higgs boson with mass in the range 90--200 GeV/c2/c^2 produced in the gluon-gluon fusion, WHWH, ZHZH, ttˉHt{\bar{t}}H, and vector boson fusion processes, and decaying in the HbbˉH\rightarrow b{\bar{b}}, HW+WH\rightarrow W^+W^-, HZZH\rightarrow ZZ, Hτ+τH\rightarrow\tau^+\tau^-, and HγγH\rightarrow \gamma\gamma modes. The data correspond to integrated luminosities of up to 10 fb1^{-1} and were collected at the Fermilab Tevatron in ppˉp{\bar{p}} collisions at s=1.96\sqrt{s}=1.96 TeV. The searches are also interpreted in the context of fermiophobic and fourth generation models. We observe a significant excess of events in the mass range between 115 and 140 GeV/c2c^2. The local significance corresponds to 3.0 standard deviations at mH=125m_H=125 GeV/c2c^2, consistent with the mass of the Higgs boson observed at the LHC, and we expect a local significance of 1.9 standard deviations. We separately combine searches for HbbˉH \to b\bar{b}, HW+WH \to W^+W^-, Hτ+τH\rightarrow\tau^+\tau^-, and HγγH\rightarrow\gamma\gamma. The observed signal strengths in all channels are consistent with the presence of a standard model Higgs boson with a mass of 125 GeV/c2c^2
    corecore