Showing papers by "Tata Institute of Fundamental Research published in 2002"
TL;DR: Some interesting trends on chewing patterns have emerged from recent data, suggesting a decline in the habit in some countries such as Thailand while the prevalence of areca nut use is rising in India and Taiwan.
Abstract: A substantial proportion of the world's population is engaged in chewing areca nut and the habit is endemic throughout the Indian subcontinent, large parts of south Asia and Melanesia. A large variety of ingredients, including tobacco, may be used along with areca nut constituting a betel quid. The composition and method of chewing can vary widely from country to country and these population variations are described in this review. Some populations are known to use areca nut without tobacco providing good opportunities to further research the carcinogenecity of areca nut. Some interesting trends on chewing patterns have emerged from recent data, suggesting a decline in the habit in some countries such as Thailand while the prevalence of areca nut use is rising in India and Taiwan.
556 citations
Journal Article•
TL;DR: The B meson decay modes B -->Dpp; and B-->D(*)pp; have been studied using 29.4 fb(-1) of data collected with the Belle detector at KEKB using the corresponding upper limits at 90% C.L. are presented.
Abstract: The B meson decay modes B → Dpp and B → D*pp have been studied using 29.4 fb - 1 of data collected with the Belle detector at KEKB. The B 0 → D 0 pp and B 0 → D* 0 pp decays have been observed for the first time with branching fractions B(B 0 → D 0 pp) = (1.18 ′ 0.15 ′ 0.16) X 10 - 4 and B(B 0 → D* 0 pp) = (1.20 + 0 . 3 3 - 0 . 2 9 ′ 0.21) X 10 - 4 . No signal has been found for the B + → D + pp and B + → D* + pp decay modes, and the corresponding upper limits at 90% C.L. are presented.
441 citations
TL;DR: In this paper, the authors review the microscopic formulation of the five-dimensional black hole of type IIB string theory in terms of the D1-D5 brane system and discuss some applications of the AdS/CFT correspondence in the context of black hole formation in three dimensions by thermal transition and by collision of point particles.
440 citations
TL;DR: In this paper, the authors study novel type IIB compactifications on the T^6/Z_2 orientifold, where the RR tadpoles can be cancelled either partially or fully by turning on three-form flux in the compact geometry.
Abstract: We study novel type IIB compactifications on the T^6/Z_2 orientifold. This geometry arises in the T-dual description of Type I theory on T^6, and one normally introduces 16 space-filling D3-branes to cancel the RR tadpoles. Here, we cancel the RR tadpoles either partially or fully by turning on three-form flux in the compact geometry. The resulting (super)potential for moduli is calculable. We demonstrate that one can find many examples of N=1 supersymmetric vacua with greatly reduced numbers of moduli in this system. A few examples with N>1 supersymmetry or complete supersymmetry breaking are also discussed.
358 citations
TL;DR: In this paper, the authors review the microscopic formulation of the five dimensional black hole of type IIB string theory in terms of the D1-D5 brane system and show how the low energy brane dynamics combined with crucial inputs from AdS/CFT correspondence leads to a derivation of black hole thermodynamics and the rate of Hawking radiation.
Abstract: In this Report we review the microscopic formulation of the five dimensional black hole of type IIB string theory in terms of the D1-D5 brane system. The emphasis here is more on the brane dynamics than on supergravity solutions. We show how the low energy brane dynamics, combined with crucial inputs from AdS/CFT correspondence, leads to a derivation of black hole thermodynamics and the rate of Hawking radiation. Our approach requires a detailed exposition of the gauge theory and conformal field theory of the D1-D5 system. We also discuss some applications of the AdS/CFT correspondence in the context of black hole formation in three dimensions by thermal transition and by collision of point particles.
317 citations
TL;DR: In this article, an infinite number of conserved currents and charges in the semiclassical limit λ → ∞ of string theory in AdS 5 × S 5 and remark on their relevance to conserved charges in dual gauge theory were found.
250 citations
TL;DR: In this paper, an analysis of supersymmetric dark matter under the Yukawa unification constraint is given, which utilizes the recently discovered region of the parameter space of models with nonuniversalities of the gaugino masses.
Abstract: An analysis of supersymmetric dark matter under the Yukawa unification constraint is given. The analysis utilizes the recently discovered region of the parameter space of models with gaugino mass nonuniversalities where large negative supersymmetric corrections to the b quark mass appear to allow $b\ensuremath{-}\ensuremath{\tau}$ unification for a positive $\ensuremath{\mu}$ sign consistent with the $\stackrel{\ensuremath{\rightarrow}}{b}s+\ensuremath{\gamma}$ and ${g}_{\ensuremath{\mu}}\ensuremath{-}2$ constraints. In the present analysis we use the revised theoretical determination of ${a}_{\ensuremath{\mu}}^{\mathrm{SM}}$ $[{a}_{\ensuremath{\mu}}{=(g}_{\ensuremath{\mu}}\ensuremath{-}2)/2]$ in computing the difference ${a}_{\ensuremath{\mu}}^{\mathrm{expt}}\ensuremath{-}{a}_{\ensuremath{\mu}}^{\mathrm{SM}}$ which takes into account a reevaluation of the light by light contribution, which has a positive sign. The analysis shows that the region of parameter space with nonuniversalities of the gaugino masses that allows for unification of Yukawa couplings also contains regions that allow the satisfaction of the relic density constraint. Specifically, we find that the lightest neutralino mass consistent with the relic density constraint, $b\ensuremath{\tau}$ unification for SU(5), and $b\ensuremath{-}t\ensuremath{-}\ensuremath{\tau}$ unification for SO(10), in addition to other constraints, lies in the region below 80 GeV. An analysis of the maximum and the minimum neutralino-proton scalar cross sections for the allowed parameter space, including the effect of a new determination of the pion-nucleon sigma term, is also given. It is found that the full parameter space for this class of models can be explored in the next generation of proposed dark matter detectors.
211 citations
TL;DR: In this paper, the authors report the observation of prompt $J/\ensuremath{\psi}$ via double $c\overline{c}$ production from the ${e}^{+}{e}^{\ENSuremath{-}}$ continuum.
Abstract: We report the observation of prompt $J/\ensuremath{\psi}$ via double $c\overline{c}$ production from the ${e}^{+}{e}^{\ensuremath{-}}$ continuum. In this process one $c\overline{c}$ pair fragments into a $J/\ensuremath{\psi}$ meson while the remaining pair either produces a charmonium state or fragments into open charm. Both cases have been experimentally observed. We find cross sections of $\ensuremath{\sigma}[{e}^{+}{e}^{\ensuremath{-}}\ensuremath{\rightarrow}J/\ensuremath{\psi}{\ensuremath{\eta}}_{c}(\ensuremath{\gamma})]\ifmmode\times\else\texttimes\fi{}\mathcal{B}({\ensuremath{\eta}}_{c}\ensuremath{\rightarrow}\ensuremath{\ge}4\text{ }\text{ }\mathrm{\text{charged}})=({0.033}_{\ensuremath{-}0.006}^{+0.007}\ifmmode\pm\else\textpm\fi{}0.009)\text{ }\text{ }\mathrm{p}\mathrm{b}$ and $\ensuremath{\sigma}({e}^{+}{e}^{\ensuremath{-}}\ensuremath{\rightarrow}J/\ensuremath{\psi}{D}^{*+}X)=({0.53}_{\ensuremath{-}0.15}^{+0.19}\ifmmode\pm\else\textpm\fi{}0.14)\text{ }\text{ }\mathrm{p}\mathrm{b}$ and infer $\ensuremath{\sigma}({e}^{+}{e}^{\ensuremath{-}}\ensuremath{\rightarrow}J/\ensuremath{\psi}c\overline{c})/\ensuremath{\sigma}({e}^{+}{e}^{\ensuremath{-}}\ensuremath{\rightarrow}J/\ensuremath{\psi}X)={0.59}_{\ensuremath{-}0.13}^{+0.15}\ifmmode\pm\else\textpm\fi{}0.12$. These results are obtained from a $46.2\text{ }\text{ }{\mathrm{f}\mathrm{b}}^{\ensuremath{-}1}$ data sample collected near the $\ensuremath{\Upsilon}(4S)$ resonance, with the Belle detector at the KEKB collider.
200 citations
TL;DR: The study indicates that depletion of norepinephrine by the selective noradrenergic neurotoxin, N‐(2‐chloroethyl)‐N‐ethyl‐2‐bromo benzylamine hydrochloride (DSP‐4), results in a 63% reduction in the proliferation of dentate gyrus progenitor cells identified through 5‐bomo‐2′‐deoxyuridine (BrdU) labelling.
Abstract: The dentate gyrus region retains the ability to generate neurons throughout adulthood. A few studies have examined the neurotransmitter regulation of adult hippocampal neurogenesis and have shown that this process is regulated by serotonin and glutamate. Given the strong noradrenergic innervation of the adult hippocampus and the ability of norepinephrine to influence proliferation during development, we examined the influence of norepinephrine on adult hippocampal neurogenesis. Our study indicates that depletion of norepinephrine by the selective noradrenergic neurotoxin, N-(2-chloroethyl)-N-ethyl-2-bromo benzylamine hydrochloride (DSP-4), results in a 63% reduction in the proliferation of dentate gyrus progenitor cells identified through 5-bromo-2′-deoxyuridine (BrdU) labelling. In contrast, the survival of BrdU-positive cells labelled prior to treatment with DSP-4 is not influenced by norepinephrine depletion. The differentiation of BrdU labelled progenitors into neurons or glia was also not sensitive to noradrenergic depletion. These results indicate that the proliferation, but not the survival or differentiation, of adult hippocampal granule cell progenitors is affected by norepinephrine depletion.
194 citations
TL;DR: In this paper, the authors consider the gauging of L μ − L τ as an explanation of a possibly large muon anomalous magnetic moment and show how neutrino masses with bimaximal mixing may be obtained in this framework.
190 citations
TL;DR: In this article, it was shown that the pp wave limit of AdS5£M 5 compactiflcations of type IIB string theory is universal and maximally supersymmetric, as long as M 5 is smooth and preserves some supersymmetry.
Abstract: We observe that the pp wave limit of AdS5£M 5 compactiflcations of type- IIB string theory is universal, and maximally supersymmetric, as long as M 5 is smooth and preserves some supersymmetry. We investigate a speciflc case, M 5 = T 1;1 . The dualN = 1 SCFT, describing D3-branes at a conifold singularity, has operators that we identify with the oscillators of the light-cone string in the universal pp wave background. The correspondence is remarkable in that it relies on the exact spectrum of anomalous dimensions in this CFT, along with the existence of certain exceptional series of operators whose dimensions are protected only in the limit of large 't Hooft coupling. We also brie∞y examine the singular case M 5 = S 5 =Z2, for which the pp wave background becomes a Z2 orbifold of the maximally supersymmetric background by re∞ection of 4 transverse coordinates. We flnd operators in the correspondingN = 2 SCFT with the right properties to describe both the untwisted and the twisted sectors of the closed string.
TL;DR: This review will draw on both the traditional models and the new data to provide a current perspective on the nature of cellular blastoderm formation in Drosophila melanogaster.
Abstract: Embryonic development in Drosophila melanogaster begins with a rapid series of mitotic nuclear divisions, unaccompanied by cytokinesis, to produce a multi-nucleated single cell embryo, the syncytial blastoderm. The syncytium then undergoes a process of cell formation, in which the individual nuclei become enclosed in individual cells. This process of cellularization involves integrating mechanisms of cell polarity, cell–cell adhesion and a specialized form of cytokinesis. The detailed molecular mechanism, however, is highly complex and, despite extensive analysis, remains poorly understood. Nevertheless, new insights are emerging from recent studies on aspects of membrane polarization and insertion, which show that membrane components from intracellular organelles are involved. In addition, actin and actin-associated proteins have been heavily implicated while new evidence shows that microtubule cytoskeletal elements are mechanistically involved in all aspects of cellularization. This review will draw on both the traditional models and the new data to provide a current perspective on the nature of cellular blastoderm formation in Drosophila melanogaster. BioEssays 24:1012–1022, 2002. © 2002 Wiley-Periodicals, Inc.
TL;DR: In this paper, Dirichlet p-branes in the background of p-waves are constructed using the massive Green-Schwarz world-sheet action for open strings.
TL;DR: In this article, an improved measurement of the standard model CP violation parameter was presented based on a sample of $85\ifmmode\times\else\texttimes\fi{}{10}^{6}$ $B\overline{B}$ pairs collected at the ϵ-Upsilon (4S) resonance with the Belle detector at the KEKB asymmetric-energy collider.
Abstract: We present an improved measurement of the standard model CP violation parameter $\mathrm{sin}2{\ensuremath{\varphi}}_{1}$ (also known as $\mathrm{sin}2\ensuremath{\beta})$ based on a sample of $85\ifmmode\times\else\texttimes\fi{}{10}^{6}$ $B\overline{B}$ pairs collected at the $\ensuremath{\Upsilon}(4S)$ resonance with the Belle detector at the KEKB asymmetric-energy ${e}^{+}{e}^{\ensuremath{-}}$ collider. One neutral B meson is reconstructed in a $J/\ensuremath{\psi}{K}_{S}^{0},$ $\ensuremath{\psi}{(2S)K}_{S}^{0},$ ${\ensuremath{\chi}}_{c1}{K}_{S}^{0},$ ${\ensuremath{\eta}}_{c}{K}_{S}^{0},$ $J/\ensuremath{\psi}{K}^{*0},$ or $J/\ensuremath{\psi}{K}_{L}^{0}$ CP-eigenstate decay channel and the flavor of the accompanying B meson is identified from its decay products. From the asymmetry in the distribution of the time interval between the two B meson decay points, we obtain $\mathrm{sin}2{\ensuremath{\varphi}}_{1}=0.719\ifmmode\pm\else\textpm\fi{}0.074(\mathrm{stat})\ifmmode\pm\else\textpm\fi{}0.035(\mathrm{syst}).$
01 Jan 2002
TL;DR: The convex analytic approach to classical Markov decision processes wherein they are cast as a static convex programming problem in the space of measures is described.
Abstract: This article describes the convex analytic approach to classical Markov decision processes wherein they are cast as a static convex programming problem in the space of measures. Applications to multiobjective problems are described.
TL;DR: In this article, the authors summarized and put in an overall perspective studies done within the compact muon solenoid (CMS) concerning the discovery potential for squarks and gluinos, sleptons, charginos and neutralinos, sparticle mass determination methods and the detector design optimization in view of SUSY searches.
Abstract: This work summarizes and puts in an overall perspective studies done within the compact muon solenoid (CMS) concerning the discovery potential for squarks and gluinos, sleptons, charginos and neutralinos, supersymmetric (SUSY) dark matter, lightest Higgs, sparticle mass determination methods and the detector design optimization in view of SUSY searches. It represents the status of our understanding of these subjects as of summer 1997. As a benchmark we used the minimal supergravity-inspired supersymmetric standard model (mSUGRA) with a stable lightest supersymmetric particle (LSP). Discovery of supersymmetry at the large hadron collider should be relatively straightforward. It may occur through the observation of large excesses of events in missing ET plus jets, or with one or more isolated leptons. An excess of trilepton events or isolated dileptons with missing ET, exhibiting a characteristic signature in the l+l− invariant mass distribution, could also be the first manifestation of SUSY production. Squarks and gluinos can be discovered for masses in excess of 2 TeV. Charginos and neutralinos can be discovered from an excess of events in dilepton or trilepton final states. Inclusive searches can give early indications from their copious production in squark and gluino cascade decays. Indirect evidence for sleptons can also be obtained from inclusive dilepton studies. Isolation requirements and a jet veto would allow detection of both the direct chargino/neutralino production and the directly produced sleptons. Squark and gluino production may also represent a copious source of Higgs bosons through cascade decays. The lightest SUSY Higgs h → b may be reconstructed with a signal/background ratio of order 1 thanks to hard cuts on ETmiss justified by escaping LSPs. The LSP of SUSY models with conserved R-parity represents a very good candidate for cosmological dark matter. The region of parameter space where this is true is well covered by our searches, at least for tanβ = 2. If supersymmetry exists at the electroweak scale, it could hardly escape detection in CMS and the study of supersymmetry will form a central part of our physics program.
TL;DR: In this article, the authors reported the observation of a narrow peak in the invariant mass distribution in a sample of exclusive $B\ensuremath{\rightarrow}K{K}_{S}{K}^{\ensure-math{-}}{-ensureMath{\pi}}^{+}$ decays collected with the Belle detector at the KEKB asymmetric k-collider.
Abstract: We report the observation of a narrow peak in the ${K}_{S}{K}^{\ensuremath{-}}{\ensuremath{\pi}}^{+}$ invariant mass distribution in a sample of exclusive $B\ensuremath{\rightarrow}K{K}_{S}{K}^{\ensuremath{-}}{\ensuremath{\pi}}^{+}$ decays collected with the Belle detector at the KEKB asymmetric ${e}^{+}{e}^{\ensuremath{-}}$ collider. The measured mass of the peak is $M=3654\ifmmode\pm\else\textpm\fi{}6(\mathrm{s}\mathrm{t}\mathrm{a}\mathrm{t})\ifmmode\pm\else\textpm\fi{}8(\mathrm{s}\mathrm{y}\mathrm{s}\mathrm{t})\text{ }\text{ }\mathrm{M}\mathrm{e}\mathrm{V}/{c}^{2}$, and we place a 90% confidence level upper limit on the width of $\ensuremath{\Gamma}l55\text{ }\text{ }\mathrm{M}\mathrm{e}\mathrm{V}/{c}^{2}$. The properties agree with heavy-quark potential model expectations for the ${\ensuremath{\eta}}_{c}(2S)$ meson, the $n=2$ singlet $S$ charmonium state.
TL;DR: In this article, finite size effects on Neel temperature (T N) of magnetoelectric BiFeO3 system were reported for the first time, and the decrease in T N was co-related to unit cell volume contraction occurring with reduction in particle size.
Abstract: In this paper, we report for the first time finite size effects on Neel temperature (T
N) of magnetoelectric BiFeO3 system. Novel wet chemical route has been developed to produce fine particles of BiFeO3 with controlled size and size distribution. Unlike other oxide systems, lattice volume contraction has been observed with decrease in particle size. The decrease in T
N is co-related to unit cell volume contraction occurring with reduction in particle size.
TL;DR: A ‘web reader’ which ‘reads out’ the textual contents of a selected web page in Hindi or in English with Indian accent is described, which is passed on to an indigenously developed text-to-speech system for Hindi/Indian English, to generate spoken output.
Abstract: Incorporation of speech and Indian scripts can greatly enhance the accessibility of web information among common people. This paper describes a ‘web reader’ which ‘reads out’ the textual contents of a selected web page in Hindi or in English with Indian accent. The content of the page is downloaded and parsed into suitable textual form. It is then passed on to an indigenously developed text-to-speech system for Hindi/Indian English, to generate spoken output. The text-to-speech conversion is performed in three stages: text analysis, to establish pronunciation, phoneme to acoustic-phonetic parameter conversion and, lastly, parameter-to-speech conversion through a production model. Different types of voices are used to read special messages. The web reader detects the hypertext links in the web pages and gives the user the option to follow the link or continue perusing the current web page. The user can exercise the option either through a keyboard or via spoken commands. Future plans include refining the web parser, improvement of naturalness of synthetic speech and improving the robustness of the speech recognition system.
TL;DR: This work has been interested in developing strategies for designing new open-framework architectures and its utilization as a primary buildingunit, in place of the silicate or the phosphate tetrahedron commonly employed for the purpose.
Abstract: We have been interested in developing strategies for designing new open-framework architectures. One such strategy is the case of the sulfate tetrahedron and its utilization as a primary buildingunit, in place of the silicate or the phosphate tetrahedron commonly employed for the purpose.
TL;DR: The ability to tailor the size and preferred orientation of grains in the TiN thin films (by proper choice of sputtering gas) is expected to have a significant impact on the properties of these films in a variety of technological applications.
TL;DR: In this article, the authors consider = 2 moose/quiver gauge theories corresponding to N1 D3-branes at a 2/N2 singularity in the ''large moose'' limit where N1 and N2 are scaled to infinity together.
Abstract: We consider = 2 moose/quiver gauge theories corresponding to N1 D3-branes at a 2/N2 singularity in the ``large moose'' limit where N1 and N2 are scaled to infinity together. In the dual holographic description, this scaling gives rise to a maximally supersymmetric pp-wave background with a compact light-cone direction. We identify the gauge theory operators that describe the Discrete Light-Cone Quantization (DLCQ) of the string in this background. For each discrete light-cone momentum and winding sector there is a separate ground state and Fock space. The large moose/quiver diagram provides a useful graphical representation of the string and its excitations. This representation has a natural explanation in a T-dual language. The dual theory is a non-relativistic type-IIA string wound around the T-dual direction, and bound by a quadratic newtonian potential. We end with some comments on D-string/D-particle states, a possible lift to M-theory and the relation to deconstruction.
TL;DR: The entropy computed using the recent results on condensation of twisted-sector tachyons in this theory is found to be in precise agreement with the Bekenstein-Hawking entropy.
Abstract: String propagation on a cone with deficit angle 2pi(1-1 / N) is considered for the purpose of computing the entropy of a large mass black hole. The entropy computed using the recent results on condensation of twisted-sector tachyons in this theory is found to be in precise agreement with the Bekenstein-Hawking entropy.
TL;DR: In this article, the authors performed model independent and model dependent analyses of solar neutrino data including the neutral current event rate from SNO, which determined the allowed ranges of 8 B flux normalisation and the ν e survival probability more precisely than what was possible from the SK and SNO CC combination.
01 Jan 2002
TL;DR: In this article, the authors present an exposition of homogeneous dynamics, that is, the dynamical and ergodic properties of actions on the homogeneous spaces of Lie groups.
Abstract: Publisher Summary This chapter presents an exposition of homogeneous dynamics—that is, the dynamical and ergodic properties of actions on the homogeneous spaces of Lie groups. Many concepts of the modern theory of dynamical systems appeared in connection with the study of the geodesic flow on a compact surface of constant negative curvature. The algebraic nature of the phase space and the action itself allows obtaining much more advanced results as compared to the general theory of smooth dynamical systems. This can be seen in the example of smooth flows with polynomial divergence of trajectories. Homogeneous actions are discussed in the chapter and some basic examples include rectilinear flow on a torus, solvable flows on a three-dimensional locally Euclidean manifold, suspensions of toral automorphisms, nilflows on homogeneous spaces of the three-dimensional Heisenberg group, the geodesic and horocycle flows on a constant negative curvature surface, and geodesic flows on locally symmetric Riemannian spaces. The chapter presents the main link between homogeneous actions and number theory (Mahler's criterion and its consequences).
16 Nov 2002
TL;DR: The 'substate' theorem is used to give tight lower bounds for the privacy loss of bounded error quantum communication protocols for the index function problem and the k-round boundederror quantum communication complexity of the pointer chasing problem.
Abstract: We prove a fundamental theorem about the relative entropy of quantum states, which roughly states that if the relative entropy, S(/spl rho//spl par//spl sigma/)/spl Delta/=Tr /spl rho/(log /spl rho/-log /spl sigma/), of two quantum states /spl rho/ and /spl sigma/ is at most c, then /spl rho//2/sup O(c)/ 'sits inside' /spl sigma/. Using this 'substate' theorem, we give tight lower bounds for the privacy loss of bounded error quantum communication protocols for the index function problem. We also use the 'substate' theorem to give tight lower bounds for the k-round bounded error quantum communication complexity of the pointer chasing problem, when the wrong player starts, and all the log n bits of the kth pointer are desired.
TL;DR: Comparison with the reported unfolding data of the homologous enzyme, horseradish peroxidase (HRP-C), showed that SBP exhibits significantly high thermal and conformational stability, and it is shown that this enhanced structural stability of SBP relative to HRP- C arises due to the unique nature of their heme binding.
Abstract: Soybean peroxidase (SBP) obtained from the soybean seed coats belongs to class III of the plant peroxidase superfamily. Detailed circular dichroism and steady state fluorescence studies have been carried out to monitor thermal as well as denaturant-induced unfolding of SBP and apo-SBP. Melting of secondary and tertiary structures of SBP occurs with characteristic transition midpoints, Tm, of 86 and 83.5 °C, respectively, at neutral pH. Removal of heme resulted in greatly decreased thermal stability of the protein (Tm = 38 °C). The ΔG°(H2O) determined from guanidine hydrochloride-induced denaturation at 25 °C and at neutral pH is 43.3 kJ mol-1 for SBP and 9.0 kJ mol-1 for apo-SBP. Comparison with the reported unfolding data of the homologous enzyme, horseradish peroxidase (HRP-C), showed that SBP exhibits significantly high thermal and conformational stability. We show that this enhanced structural stability of SBP relative to HRP-C arises due to the unique nature of their heme binding. A stronger heme−apo...
TL;DR: In this article, the authors reported the first example of a $b\to s$ transition with baryons in the final state, where the mass spectrum in this decay is inconsistent with phase space and is peaked at low mass.
Abstract: We report the observation of the decay mode $B^{\pm}\to p \bar{p} K^{\pm}$ based on an analysis of 29.4 fb$^{-1}$ of data collected by the Belle detector at KEKB. This is the first example of a $b\to s$ transition with baryons in the final state. The $p \bar{p}$ mass spectrum in this decay is inconsistent with phase space and is peaked at low mass. The branching fraction for this decay is measured to be ${\cal B}(B^{\pm}\to p \bar{p} K^{\pm}) =(4.3^{+1.1}_{-0.9}({\rm stat})\pm 0.5({\rm syst}))\times 10^{-6}.$ We also report upper limits for the decays $B^0\to p \bar{p} K_S$ and $B^{\pm}\to p \bar{p} \pi^{\pm}$.
TL;DR: This work describes FCS in sufficient detail so that the reader is able to judge when there is a compelling reason to choose this technique, understand the basic theory behind it, construct a FCS spectrometer in the laboratory, and analyze the data to obtain a meaningful estimate of the physical parameters.
TL;DR: The first direct observations of anomalously rapid damping of plasma shielding currents produced in response to the hot electron currents penetrating the bulk plasma are presented.
Abstract: In this Letter, we present first experimental measurements of temporal evolution of Megagauss magnetic fields generated at the critical layer, on femtosecond timescales. The field generation and decay mechanisms are identified and role of resonance absorption is examined. The initial buildup of magnetic field due to direct laser radiation effects is calculated using LPIC++ code [7] and the results are found to be in good agreement with the experiment. The field evolution is explained to be due to currents generated by fast electrons [8] and plasma return currents damped by turbulence induced resistivity [9]. The first direct observation of anomalously rapid damping of return currents, which may have important consequences for laser fusion, is reported. We demonstrate ultrashort, Megagauss magnetic pulses, with 6 picosecond (FWHM) duration and a peak magnitude of 27 Megagauss generated by a p-polarized laser pulse. Possible applications of such high-field ultrashort magnetic pulses in various areas are discussed. Laser pulses (806 nm, 100 fs) are derived from a custom built chirped pulse amplification Titanium:Sapphire laser, described in detail elsewhere [10]. The linearly polarized pump pulse incident at 55 ◦ is focused on a solid target with typical intensities of 10 16 W cm −2 (Fig. 1). A small part of the laser is used to generate a linearly polarized, second harmonic (403nm) probe pulse using a thin (0.5mm) BBO crystal. The probe pulse incident at 50 ◦ , is focused to an intensity of 5 × 10 12 W cm −2 and is spatially overlapped with the pump spot. The probe penetrates beyond the critical density(nc) for pump (i.e. upto 1.65n 806 or 0.4n 403 as shown in inset of Fig.1). The probe pulse delay with respect to pump is varied using a motorized translation stage.