Prospects for New Physics in CP Violation and Rare Decays at LHCb

LHCb is the heavy flavour precision experiment of the proton-proton Large Hadron Collider (LHC) at CERN. It will search for new physics in CP violation and rare decays and is ready for the start-up of the LHC. An overview of its physics program will be given, illustrated by few key examples: measurements of the CKM angle $\gamma$, of the CP violating phase in $B_s \overline{B_s}$ oscillations and searches for new physics in $B^0_d \to K^*\mu^+\mu^-$ and in $B^0_s \to \mu^+\mu^-$.Comment: PANIC08 conference proceedings, 3 page

Status and expected performance of the LHCb experiment

LHCb is a dedicated b-physics experiment at the future LHC collider. Its construction has started and it will be ready to take data from the start of LHC operation, scheduled in 2007, and directly at its full physics potential. LHCb will benefit from an unprecedented source of b-hadrons, provided by LHC, to improve substantialy precision measurements of CP violation parameters in many different and complementary channels. The detector provides good particle identification, vertexing and has an efficient and flexible trigger. Its status and expected performance are reviewed.Comment: 8 pages, 2 figures, To appear in the Proceedings of 6th International Conference on Hyperons, Charm & Beauty Hadrons, Chicago, United States, June 27 -- July 3 200

b Physics

A summary of the most recent and important measurements in b physics is presented. The production of beauty particles in Z decays, b quark couplings, lifetimes, B0-B0bar oscillations, semileptonic b decays and studies of the number of charm quarks produced in b decays are reviewed. Extraction of the Cabibbo-Kobayashi-Maskawa (CKM) matrix elements |V_{td}|, |V_{cb}|, |V_{ub}| and implication for |V_{ts}| are discussed.Comment: 24 pages, 2 figures, Second Latin American Symposium on High Energy Physics, San Juan, Puerto Rico, April 199

Cued Speech Gesture Recognition: A First Prototype Based on Early Reduction

International audienceCued Speech is a specific linguistic code for hearing-impaired people. It is based on both lip reading and manual gestures. In the context of THIMP (Telephony for the Hearing-IMpaired Project), we work on automatic cued speech translation. In this paper, we only address the problem of automatic cued speech manual gesture recognition. Such a gesture recognition issue is really common from a theoretical point of view, but we approach it with respect to its particularities in order to derive an original method. This method is essentially built around a bioinspired method called early reduction. Prior to a complete analysis of each image of a sequence, the early reduction process automatically extracts a restricted number of key images which summarize the whole sequence. Only the key images are studied from a temporal point of view with lighter computation than the complete sequenc

Predictable composition of memory accesses on many-core processors

International audienceThe use of many-core COTS processors in safety critical embedded systems is a challenging research topic. The predictable execution of several applications on those processors is not possible without a precise analysis and mitigation of the possible sources of interference. In this paper, we identify the external DDR-SDRAM and the Network on Chip to be the main bottlenecks for both average performance and predictability in such platforms. As DDR-SDRAM memories are intrinsically stateful, the naive calculation of the Worst-Case Execution Times (WCETs) of tasks involves a significantly pessimistic upper-bounding of the memory access latencies. Moreover, the worst-case end-to-end delays of wormhole switched networks cannot be bounded without strong assumptions on the system model because of the possibility of deadlock. We provide an analysis of each potential source of interference and we give recommendations in order to build viable execution models enabling efficient composable computation of worst-case end-to-end memory access latencies compared to the naive worst-case-everywhere approach

On exact division and divisibility testing for sparse polynomials

No polynomial-time algorithm is known to test whether a sparse polynomial G divides another sparse polynomial $F$. While computing the quotient Q=F quo G can be done in polynomial time with respect to the sparsities of F, G and Q, this is not yet sufficient to get a polynomial-time divisibility test in general. Indeed, the sparsity of the quotient Q can be exponentially larger than the ones of F and G. In the favorable case where the sparsity #Q of the quotient is polynomial, the best known algorithm to compute Q has a non-linear factor #G#Q in the complexity, which is not optimal. In this work, we are interested in the two aspects of this problem. First, we propose a new randomized algorithm that computes the quotient of two sparse polynomials when the division is exact. Its complexity is quasi-linear in the sparsities of F, G and Q. Our approach relies on sparse interpolation and it works over any finite field or the ring of integers. Then, as a step toward faster divisibility testing, we provide a new polynomial-time algorithm when the divisor has a specific shape. More precisely, we reduce the problem to finding a polynomial S such that QS is sparse and testing divisibility by S can be done in polynomial time. We identify some structure patterns in the divisor G for which we can efficiently compute such a polynomial~S

Essentially Optimal Sparse Polynomial Multiplication

We present a probabilistic algorithm to compute the product of two univariate sparse polynomials over a field with a number of bit operations that is quasi-linear in the size of the input and the output. Our algorithm works for any field of characteristic zero or larger than the degree. We mainly rely on sparse interpolation and on a new algorithm for verifying a sparse product that has also a quasi-linear time complexity. Using Kronecker substitution techniques we extend our result to the multivariate case.Comment: 12 page

Détermination pratique de quelques espèces de convolvulacées, adventices de l'Afrique du Centre et de l'Ouest

Détermination pratique de quelques espèces de convolvulacées, adventices de l'Afrique du Centre et de l'Ouest. Les auteurs décrivent une clé d'identification utilisant uniquement des critères végétatifs pour 22 espèces de Convolvulaceae, adventices des cultures en Afrique du Contre et de l'Ouest. Elle est accompagnée d'une liste des synonymes usuels pour chaque espèce, d'un tableau des caractères végétatifs des espèces volubiles, d'un texte de description et de planches. Ces éléments permettent la détermination des adventices au stade végétatif à partir de caractères visibles et facilement repérables, ne nécessitant pus une formation de botaniste. (Résumé d'auteur

The mixed analog/digital shaper of the LHCb preshower

The LHCb preshower signals show so many fluctuations at low energy that a classical shaping is not usable at all. Thanks to the fact that the fraction of the collected energy during a whole LHC beam crossing time is 85%, we studied the special solution we presented at Snowmass 1999 workshop. This solution consists of 2 interleaved fast integrators, one being in integrate mode when the other is digitally reset. Two track-and-hold systems and an analog multiplexer are used to give at the output 85% of the signal plus 15% of the previous one. These 15% are digitally computed from the previous sample, and subtracted. A completely new design of this solution had to be made. This new design is described, including new methods to decrease the supply voltage and the noise, as well as to increase the quality of the reset and the linearity. An output stage, consisting of an AB class push-pull using only NPN transistors is also described. Laboratory and beam test results are given. (5 refs)

A mixed analog/digital shaper for the LHCb preshower

This note describes, first, the experimental and theoretical studies of the LHCb's preshower signals performed with a prototype cell. Four designs of the very front end electronic are then discuted and a choice is proposed