34 research outputs found

    A new window on Strange Quark Matter as the ground state of strongly interacting matter

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    If strange quark matter is the true ground state of matter, it must have lower energy than nuclear matter. Simultaneously, two-flavour quark matter must have higher energy than nuclear matter, for otherwise the latter would convert to the former. We show, using an effective chiral lagrangian, that the existence of a new lower energy ground state for two-flavour quark matter, the pion condensate, shrinks the window for strange quark matter to be the ground state of matter and sets new limits on the current strange quark mass

    Extended Skyrme interaction (I): spin fluctuations in dense matter

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    Most of the Skyrme interactions are known to predict spin or isospin instabilities beyond the saturation density of nuclear matter which contradict predictions based on realistic interactions. A modification of the standard Skyrme interaction is proposed so that the ferromagnetic instability is removed. The new terms are density dependent and modify only the spin p-h interaction in the case of spin-saturated system. Consequences for the nuclear response function and neutrino mean free path are shown. The overall effect of the RPA correlations makes dense matter more transparent for neutrino propagation by a factor of 2 to 10 depending of the density.Comment: 6 pages, 5 Figs., 2 Tab

    Lattice Matrix Elements and CP Violation in B and K Physics: Status and Outlook

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    Status of lattice calculations of hadron matrix elements along with CP violation in B and in K systems is reviewed. Lattice has provided useful input which, in conjunction with experimenatl data, leads to the conclusion that CP-odd phase in the CKM matrix plays the dominant role in the observed asymmetry in B→ψKsB \to \psi K_s. It is now quite likely that any beyond the SM, CP-odd, phase will cause only small deviations in B-physics. Search for the effects of the new phase(s) will consequently require very large data samples as well as very precise theoretical predictions. Clean determination of {\it all} the angles of the unitarity triangle therefore becomes essential. In this regard B→KD0B \to K D^0 processes play a unique role. Regarding K-decays, remarkable progress made by theory with regard to maintenance of chiral symmetry on the lattice is briefly discussed. First application already provide quantitaive information on BKB_K and the ΔI=1/2\Delta I=1/2 rule. The enhancement in ReA0Re A_0 appears to arise solely from tree operators, esp. Q2Q_2; penguin contribution to ReA0Re A_0 appears to be very small. However, improved calculations are necessary for \epsilon^'/epsilon as there the contributions of QCD penguins and electroweak penguins largely seem to cancel. There are good reasons, though, to believe that these cancellations will not survive improvements that are now underway. Importance of determining the unitarity triangle purely from K-decays is also emphasized.Comment: Invited talk at the 9th International Symposium on Particles, Strings and Cosmology (PASCOS 03), Mumbai (Bombay) India,3-8 Jan 200

    A calculation of the BBB_{B} parameter in the static limit

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    We calculate the BBB_{B} parameter, relevant for B‟0\overline{B}^0 -- B0B^0 mixing, from a lattice gauge theory simulation at ÎČ=6.0\beta = 6.0. The bottom quarks are simulated in the static theory, the light quarks with Wilson fermions. Improved smearing functions produced by a variational technique, MOST, are used to reduce statistical errors and minimize excited-state contamination of the ground-state signal. We obtain BB(4.33GeV)=0.98−4+4B_B(4.33 GeV) = 0.98^{+4}_{-4} (statistical) −18+3^{+3}_{-18} (systematic) which corresponds to B^B=1.40−6+6\widehat{B}_B = 1.40^{+6}_{-6} (statistical) −26+4^{+4}_{-26} (systematic) for the one-loop renormalization-scheme-independent parameter. The systematic errors include the uncertainty due to alternative (less favored) treatments of the perturbatively-calculated mixing coefficients; this uncertainty is at least as large as residual differences between Wilson-static and clover-static results. Our result agrees with extrapolations of results from relativistic (Wilson) heavy quark simulations.Comment: 39 pages (REVTeX) including 10 figures (PostScript); Final version accepted for publication: Added new section for clarity; Included comparison to recent results by other groups; slight numerical changes; Essential conclusions remain the sam

    Search for a heavy bottom-like quark in pp collisions at √s =7 TeV

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    This is the Pre-Print version of the Article. The official published version of the paper can be accessed from the link below - Copyright @ 2011 Elsevier.A search for pair-produced bottom-like quarks in pp collisions at sqrt(s) = 7 TeV is conducted with the CMS experiment at the LHC. The decay b' to tW is considered in this search. The b' b'-bar to tW^- t-bar W^+ process can be identified by the distinctive signature of trileptons and same-sign dileptons. With a data sample corresponding to an integrated luminosity of 34 inverse picobarns, no excess above the standard model background predictions is observed and a b' quark with a mass between 255 and 361 GeV/c^2 is excluded at the 95% confidence level.This work is supported by the FMSR (Austria); FNRS and FWO (Belgium); CNPq, CAPES, FAPERJ, and FAPESP (Brazil); MES (Bulgaria); CERN; CAS, MoST, and NSFC (China); COLCIENCIAS (Colombia); MSES (Croatia); RPF (Cyprus); Academy of Sciences and NICPB (Estonia); Academy of Finland, ME, and HIP (Finland); CEA and CNRS/IN2P3 (France); BMBF, DFG, and HGF (Germany); GSRT (Greece); OTKA and NKTH (Hungary); DAE and DST (India); IPM (Iran); SFI (Ireland); INFN (Italy); NRF and WCU (Korea); LAS (Lithuania); CINVESTAV, CONACYT, SEP, and UASLP-FAI (Mexico); PAEC (Pakistan); SCSR (Poland); FCT (Portugal); JINR (Armenia, Belarus, Georgia, Ukraine, Uzbekistan); MST and MAE (Russia); MSTD (Serbia); MICINN and CPAN (Spain); Swiss Funding Agencies (Switzerland); NSC (Taipei); TUBITAK and TAEK (Turkey); STFC (United Kingdom); DOE and NSF (USA)

    2016 United Kingdom national guideline on the sexual health care of men who have sex with men.

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    This guideline is intended for use in UK Genitourinary medicine clinics and sexual health services but is likely to be of relevance in all sexual health settings, including general practice and Contraception and Sexual Health (CASH) services, where men who have sex with men (MSM) seek sexual health care or where addressing the sexual health needs of MSM may have public health benefits. For the purposes of this document, MSM includes all gay, bisexual and all other males who have sex with other males and both cis and trans men. This document does not provide guidance on the treatment of particular conditions where this is covered in other British Association for Sexual Health and HIV (BASHH) Guidelines but outlines best practice in multiple aspects of the sexual health care of MSM. Where prevention of sexually transmitted infections including HIV can be addressed as an integral part of clinical care, this is consistent with the concept of combination prevention and is included. The document is designed primarily to provide guidance on the direct clinical care of MSM but also makes reference to the design and delivery of services with the aim of supporting clinicians and commissioners in providing effective services. Methodology This document was produced in accordance with the guidance set out in the BASHH CEG's document 'Framework for guideline development and assessment' published in 2010 at http://www.bashh.org/guidelines and with reference to the Agree II instrument. Following the production of the updated framework in April 2015, the GRADE system for assessing evidence was adopted and the draft recommendations were regraded. Search strategy (see also Appendix 1) Ovid Medline 1946 to December 2014, Medline daily update, Embase 1974 to December 2014, Pubmed NeLH Guidelines Database, Cochrane library from 2000 to December 2014. Search language English only. The search for Section 3 was conducted on PubMed to December 2014. Priority was given to peer-reviewed papers published in scientific journals, although for many issues evidence includes conference abstracts listed on the Embase database. In addition, for 'Identification of problematic recreational drug and alcohol use' section and 'Sexual problems and dysfunctions in MSM' section, searches included PsycINFO. Methods Article titles and abstracts were reviewed and if relevant the full text article was obtained. Priority was given to randomised controlled trial and systematic review evidence, and recommendations made and graded on the basis of best available evidence. Piloting and feedback The first draft of the guideline was circulated to the writing group and to a small group of relevant experts, third sector partners and patient representatives who were invited to comment on the whole document and specifically on particular sections. The revised draft was reviewed by the CEG and then reviewed by the BASHH patient/public panel and posted on the BASHH website for public consultation. The final draft was piloted before publication. Guideline update The guidelines will be reviewed and revised in five years' time, 2022

    Physics of the HL-LHC, and perspectives at the HE-LH: report from working group 4: opportunities in flavour physics at the HL-LHC and HE-LHC

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    Motivated by the success of the flavour physics programme carried out over the last decade at the Large Hadron Collider (LHC), we characterize in detail the physics potential of its High-Luminosity and High-Energy upgrades in this domain of physics. We document the extraordinary breadth of the HL/HE-LHC programme enabled by a putative Upgrade II of the dedicated flavour physics experiment LHCb and the evolution of the established flavour physics role of the ATLAS and CMS general purpose experiments. We connect the dedicated flavour physics programme to studies of the top quark, Higgs boson, and direct high-pT searches for new particles and force carriers. We discuss the complementarity of their discovery potential for physics beyond the Standard Model, affirming the necessity to fully exploit the LHC’s flavour physics potential throughout its upgrade eras
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