Prospects for the Precision Measurement of the W Mass with the CMS Detector at the LHC

The precise measurement of the mass of the W boson constitutes an important consistency check of the Standard Model and is sensitive to supersymmetric corrections. Together with the top quark mass, the W mass discriminates between the Standard Model and supersymmetric extensions. In this note, methods are presented which employ the large number of Z bosons produced at the LHC to significantly reduce theoretical and experimental uncertainties on the W mass measurement. A precision of about 40 MeV (20 MeV) with the first 1 fb^-1 (10 fb^-1) of integrated luminosity during the low luminosity run of the LHC is expected

Re-evaluation of the LHC potential for the measurement of Mw

We present a study of the LHC sensitivity to the W boson mass based on simulation studies. We find that both experimental and phenomenological sources of systematic uncertainties can be strongly constrained with Z measurements: the lineshape is robustly predicted, and its analysis provides an accurate measurement of the detector resolution and absolute scale, while the differential cross-section analysis absorbs most of the strong interaction uncertainties. A sensitivity \delta Mw \sim 7 \MeV for each decay channel (W --> e nu, W --> mu nu), and for an integrated luminosity of 10 fb-1, appears as a reasonable goal

Measurement of MW+ - MW- at LHC

This paper is the second of the series of papers proposing dedicated strategies for precision measurements of the Standard Model parameters at the LHC. The common feature of these strategies is their robustness with respect to the systematic measurement and modeling error sources. Their impact on the precision of the measured parameters is reduced using dedicated observables and dedicated measurement procedures which exploit flexibilities of the collider and detector running modes. In the present paper we focus our attention on the measurement of the charge asymmetry of the W-boson mass. This measurement is of primordial importance for the LHC experimental program, both as a direct test of the charge-sign-independent coupling of the W-bosons to the matter particles and as a necessary first step towards the precision measurement of the charge-averaged W-boson mass. We propose and evaluate the LHC-specific strategy to measure the mass difference between the positively and negatively charged W-bosons, MW+ - MW-. We show that its present precision can be improved at the LHC by a factor of 20. We argue that such a precision is beyond the reach of the standard measurement and calibration methods imported to the LHC from the Tevatron program.Comment: 39 pages, 8 figure

Standard Model Handles and Candles Working Group: Tools and Jets Summary Report

This report summarizes the activity on comparisons of existings tools for the standard model and on issues in jet physics by the SMHC working group during and subsequent to the Workshop "Physics at TeV Colliders", Les Houches, France, 11-29 June, 2007.Comment: 94 pages, LaTeX, many figures. Summary report of the tools and jets parts of the SMHC working group of the Les Houches 2007 workshop "Physics at TeV Colliders", Les Houches, France, 11-29 June, 200

High cryptic diversity in the kleptoparasitic genus Hyalorisia Dall, 1889 (Littorinimorpha: Capulidae) with the description of nine new species from the Indo-West Pacific

Species in the family Capulidae (Littorinimorpha: Capuloidea) display a wide range of shell morphologies. Several species are known to live in association with other benthic invertebrates-mostly bivalves and sabellid worms, but also other gastropods-and are believed to be kleptoparasitic filter feeders that take advantage of the water current produced by the host. This peculiar trophic ecology, implying a sedentary lifestyle, has resulted in highly convergent shell forms. This is particularly true for the genus Hyalorisia Dall, 1889, which occurs in deep water in the Caribbean and Indo-West Pacific provinces, with two nominal species recognized so far. Combining morphological, ecological and molecular data, we assessed the diversity of the genus, its phylogenetic position inside the family and its association with its bivalve host, the genus Propeamussium de Gregorio, 1884 (Pectinoidea), resulting in the description of nine new cryptic species. When sympatric, species of Hyalorisia are associated with different host species, but the same species of Propeamussium may be the host of several allopatric species of Hyalorisia