DOCSLIB.ORG

Search for Non Standard Model Higgs Boson

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Search for Non Standard Model Higgs Boson Thirteenth Conference on the Intersections of Particle and Nuclear Physics May 29 – June 3, 2018 Palm Springs, CA Search for Non Standard Model Higgs Boson Ana Elena Dumitriu (IFIN-HH, CPPM), On behalf of the ATLAS Collaboration 5/18/18 1 Introduction and Motivation ● The discovery of the Higgs (125 GeV) by ATLAS and CMS collaborations → great success of particle physics and especially Standard Model (SM) ● However.... – MORE ROOM Hierarchy problem FOR HIGGS PHYSICS – Origin of dark matter, dark energy BEYOND SM – Baryon Asymmetry – Gravity – Higgs br to Beyond Standard Model (BSM) particles of BRBSM < 32% at 95% C.L. ● !!!!!!There is plenty of room for Higgs physics beyond the Standard Model. ● There are several theoretical models with an extended Higgs sector. – 2 Higgs Doublet Models (2HDM). Having two complex scalar SU(2) doublets, they are an effective extension of the SM. In total, 5 different Higgs bosons are predicted: two CP even and one CP odd electrically neutral Higgs bosons, denoted by h, H, and A, respectively, and two charged Higgs bosons, H±. The parameters used to describe a 2HDM are the Higgs boson masses and the ratios of their vacuum expectation values. ● type I, where one SU(2) doublet gives masses to all leptons and quarks and the other doublet essentially decouples from fermions ● type II, where one doublet gives mass to up-like quarks (and potentially neutrinos) and the down-type quarks and leptons receive mass from the other doublet. – Supersymmetry (SUSY), which brings along super-partners of the SM particles. The Minimal Supersymmetric Standard Model (MSSM), whose Higgs sector is equivalent to the one of a constrained 2HDM of type II and the next-to MSSM (NMSSM) are among the experimentally best tested models, because they provide good benchmarks for SUSY. – General searches – Invisible decaying Higgs boson 2 Search for doubly-charged scalar bosons decaying to same-sign W bosons HIGG-2016-09: Phenomenology ● The scalar sector of the Standard Model is one of the main candidates to host new particles and forces beyond the SM ● A variant of such an extension: a hypercharge Y = 2 scalar triplet, ∆, complements the SM scalar doublet H. ● The renormalizable scalar potential V(H, ∆) is defined in its most general form by: Pair production (done in Rel 20.7): pp →γ*,Z* → H±±H∓∓ Associated production: pp → W*+ → H±±H∓ Single production: pp → W±*W±* → H±± (proportional to vt, negligible) ● Benchmark points considered: mH±± ranging from 200 − 700 GeV in steps of 100 GeV ● As in all analysis: – SR: 3 channels considered, optimized using TMVA CutsSA ● Dominant backgrounds: – 2Lss : WW , WZ, Vγ contribute to the prompt sources; Z+jets, tt contribute to fake backgrounds; +QmisID from W ±W ∓ and Z+jets. – 3L: WZ, ZZ, Vγ, ttV contribute to prompt backgrounds.; Z+jets and tt contribute to fakes. ; No QmisID. – 4L: ZZ and tt Z contribute to prompt sources; Fakes originate from Z+jets and tt . ● Prompt sources are estimated from MC. ● Fake estimation: – 2Lss and 3L: Data-driven fake factor method is used (FF) – 4L: using MC, with corrections applied based on MC-data agreement in the control regions. 3 Search for doubly-charged scalar bosons decaying to same-sign W bosons HIGG-2016-09: Results mH++ = 200 GeV ● A search for the pair production of doubly charged Higgs is performed through the selection of multi-lepton events with MET + jets. ● No significant excess is observed in data. Combining those channels, the model is excluded at 95% C.L. for masses of up to approximately 239 GeV. ● Further steps: – Perform the analysis with the two AP and PP production modes – Optimize the SR definition, fake estimation – Use of the ttH analysis synergy and derived data set – Goal: Increase drastically the observed limit (>300GeV) with PP+AP production mode @ 80fb-1 4 Search for doubly charged Higgs boson production in multi-lepton final states, 36.1 fb-1 (link) ● This analysis focuses on BSM theories that contain a doubly charged Higgs particle H±± using the observed invariant mass of same-charge lepton pairs. The analysis targets only decays of the H particle into electrons and muons, denoted by ℓ (with 2,3,4-lepton SR) + further divided into unique flavour categories (e or μ) to increase the sensitivity. ● Doubly charged Higgs bosons can arise in a large variety of BSM theories, namely in left-right symmetric (LRS) models, Higgs triplet models, the little Higgs model, type-II see-saw models, the Georgi–Machacek model, scalar singlet dark matter, and the Zee–Babu neutrino mass model. ● No significant excess above the Standard Model prediction was found → lower limits are set on the mass of doubly-charged Higgs bosons: ±± ±± ± ± ±± ± ± – 770 GeV and 870 GeV for the H L mass and for B(H →ℓ ℓ ) = 100% and >450 GeV for B(H →ℓ ℓ )≥10% for any combination of partial branching ratios. ±± ±± ± ± ±± ± ± – on the H R mass vary from 660 GeV to 760 GeV for B(H → ℓ ℓ ) = 100% and are above 320 GeV for B(B(H → ℓ ℓ )≥10% ● The observed limits are consistent with the expected limits. 5 Search for an invisibly decaying Higgs boson or dark matter candidates produced in association with a Z boson (link) ● -3 The Higgs boson (H→ZZ→ νννν) has a branching ratio BH→inv of 1.06x10 for mH = 125 GeV, a larger BH→inv can exist in many extensions of the SM (a Higgs boson can decay to light neutralinos, graviscalars in extra-dimension models, Majorons, neutrinos, or dark matter (DM) through the Higgs portal model). ● Observation of a BH→inv significantly above the SM value would give a strong indication for physics BSM. ● Moreover, models with a sizable BH→inv often involve a Higgs boson decaying into WIMPs. ● miss The search is carried out in the ℓℓ + E T final state, no significant data excess above the expectation of the SM backgrounds. ● An observed (expected) upper limit of 67% (39%) is set on BH→inv at the 95% CL for mH = 125 GeV [75% (62%) derived in the same final state using the ATLAS data √s= 7 and 8 TeV] ● The corresponding observed (expected) limit on the production cs of the ZH process with prompt Z→ ee and Z → μμ decays and invisible Higgs boson decays is 40 (23) fb at the 95% CL. ● Exclusion limits are placed on masses in a simplified dark matter model with an axial-vector mediator and fermionic WIMPs: mmed is excluded up to 560 GeV at the 95% CL for a light WIMP, while the WIMP mass m is excluded up to 130 GeV for mmed = 400 GeV. 6 Search for additional heavy neutral Higgs and gauge bosons in the ditau final state produced (link) ● Heavy Z' gauge bosons appear in many extensions of the SM. In particular, models in which the Z' boson couples preferentially to third-generation fermions may be linked to the high mass of the top quark or to recent indications of lepton flavour universality violation in semi-tauonic B meson decays. ● Search for neutral MSSM Higgs bosons as well as high-mass Z' resonances in the ditau decay mode, in the lephad and hadhad decay modes (lep represents the decay of a τ-lepton to an electron or a muon and neutrinos, had represents the decay to one or more hadrons and a neutrino). ● Narrow resonances with masses of 0.2–2.25 TeV and tanβ of 1–58 for the MSSM Higgs bosons. ● No indication of an excess over the expected SM background is found, upper limits on the cross section for the production of scalar and Z' bosons times the branching fraction to ditau final states are set at 95% CL: 0.78–0.0058 pb (0.70–0.0037 pb) for gluon–gluon fusion (b-associated) production of scalar bosons with masses of 0.2–2.25 TeV and 1.56–0.0072 pb for Drell–Yan production of Z0 bosons with masses of 0.2– 4 TeV. ● In the context of the hMSSM scenario, the most stringent limits for the combined search exclude tanβ> 1.0 for mA = 0.25 TeV and tanβ> 42 for mA = 1.5 TeV at 95% CL. ● In the context of the Sequential Standard Model, Z'SSM bosons with masses less than 2.42 TeV are excluded at 95% 2 7 CL, while mZ'NU < 2.25–2.60 TeV is excluded in the range 0.03 < sin φ < 0.5 in the non-universal G(221) model. Search for Higgs boson decays to beyond-the- Standard-Model light bosons in four-lepton (link) ● Exotic Higgs boson decays have been proposed as a way to search for evidence of new physics → the addition of even a small coupling to a new light state could open up sizeable new decay modes. In addition, new particles may couple preferentially to the Higgs boson since it provides a possible “portal” for hidden-sector particles to interact with SM particles. ● The processes under study here are referred to as pp → H → ZX/XX → 4ℓ, with Z being the SM Z boson and with X representing a possible new vector boson Zd or a new pseudoscalar boson a; same-flavour decays of the new particle to pairs of electrons and muons are considered. ● Two well-motivated benchmark models that predict exotic decays to light beyond-the-Standard-Model (BSM) bosons: – higher mass range: the SM is extended with a dark-sector U(1) group, denoted U(1)d, leading to the appearance of a BSM vector boson, Zd. – lower mass range: two Higgs doublets and an additional singlet scalar field (2HDM+S).
Load more

Recommended publications
  • Basic Ideas of the Standard Model
    BASIC IDEAS OF THE STANDARD MODEL V.I. ZAKHAROV Randall Laboratory of Physics University of Michigan, Ann Arbor, Michigan 48109, USA Abstract This is a series of four lectures on the Standard Model. The role of conserved currents is emphasized. Both degeneracy of states and the Goldstone mode are discussed as realization of current conservation. Remarks on strongly interact- ing Higgs fields are included. No originality is intended and no references are given for this reason. These lectures can serve only as a material supplemental to standard textbooks. PRELIMINARIES Standard Model (SM) of electroweak interactions describes, as is well known, a huge amount of exper- imental data. Comparison with experiment is not, however, the aspect of the SM which is emphasized in present lectures. Rather we treat SM as a field theory and concentrate on basic ideas underlying this field theory. Th Standard Model describes interactions of fields of various spins and includes spin-1, spin-1/2 and spin-0 particles. Spin-1 particles are observed as gauge bosons of electroweak interactions. Spin- 1/2 particles are represented by quarks and leptons. And spin-0, or Higgs particles have not yet been observed although, as we shall discuss later, we can say that scalar particles are in fact longitudinal components of the vector bosons. Interaction of the vector bosons can be consistently described only if it is highly symmetrical, or universal. Moreover, from experiment we know that the corresponding couplings are weak and can be treated perturbatively. Interaction of spin-1/2 and spin-0 particles are fixed by theory to a much lesser degree and bring in many parameters of the SM.
    [Show full text]
  • Three Lectures on Meson Mixing and CKM Phenomenology
    Three Lectures on Meson Mixing and CKM phenomenology Ulrich Nierste Institut f¨ur Theoretische Teilchenphysik Universit¨at Karlsruhe Karlsruhe Institute of Technology, D-76128 Karlsruhe, Germany I give an introduction to the theory of meson-antimeson mixing, aiming at students who plan to work at a flavour physics experiment or intend to do associated theoretical studies. I derive the formulae for the time evolution of a neutral meson system and show how the mass and width differences among the neutral meson eigenstates and the CP phase in mixing are calculated in the Standard Model. Special emphasis is laid on CP violation, which is covered in detail for K−K mixing, Bd−Bd mixing and Bs−Bs mixing. I explain the constraints on the apex (ρ, η) of the unitarity triangle implied by ǫK ,∆MBd ,∆MBd /∆MBs and various mixing-induced CP asymmetries such as aCP(Bd → J/ψKshort)(t). The impact of a future measurement of CP violation in flavour-specific Bd decays is also shown. 1 First lecture: A big-brush picture 1.1 Mesons, quarks and box diagrams The neutral K, D, Bd and Bs mesons are the only hadrons which mix with their antiparticles. These meson states are flavour eigenstates and the corresponding antimesons K, D, Bd and Bs have opposite flavour quantum numbers: K sd, D cu, B bd, B bs, ∼ ∼ d ∼ s ∼ K sd, D cu, B bd, B bs, (1) ∼ ∼ d ∼ s ∼ Here for example “Bs bs” means that the Bs meson has the same flavour quantum numbers as the quark pair (b,s), i.e.∼ the beauty and strangeness quantum numbers are B = 1 and S = 1, respectively.
    [Show full text]
  • Strong Coupling Constants of the Doubly Heavy $\Xi {QQ} $ Baryons
    Strong Coupling Constants of the Doubly Heavy ΞQQ Baryons with π Meson A. R. Olamaei1,4, K. Azizi2,3,4, S. Rostami5 1 Department of Physics, Jahrom University, Jahrom, P. O. Box 74137-66171, Iran 2 Department of Physics, University of Tehran, North Karegar Ave. Tehran 14395-547, Iran 3 Department of Physics, Doˇgu¸sUniversity, Acibadem-Kadik¨oy, 34722 Istanbul, Turkey 4 School of Particles and Accelerators, Institute for Research in Fundamental Sciences (IPM), P. O. Box 19395-5531, Tehran, Iran 5 Department of Physics, Shahid Rajaee Teacher Training University, Lavizan, Tehran 16788, Iran Abstract ++ The doubly charmed Ξcc (ccu) state is the only listed baryon in PDG, which was discovered in the experiment. The LHCb collaboration gets closer to dis- + covering the second doubly charmed baryon Ξcc(ccd), hence the investigation of the doubly charmed/bottom baryons from many aspects is of great importance that may help us not only get valuable knowledge on the nature of the newly discovered states, but also in the search for other members of the doubly heavy baryons predicted by the quark model. In this context, we investigate the strong +(+) 0(±) coupling constants among the Ξcc baryons and π mesons by means of light cone QCD sum rule. Using the general forms of the interpolating currents of the +(+) Ξcc baryons and the distribution amplitudes (DAs) of the π meson, we extract the values of the coupling constants gΞccΞccπ. We extend our analyses to calculate the strong coupling constants among the partner baryons with π mesons, as well, and extract the values of the strong couplings gΞbbΞbbπ and gΞbcΞbcπ.
    [Show full text]
  • Introduction to Supersymmetry
    Introduction to Supersymmetry Pre-SUSY Summer School Corpus Christi, Texas May 15-18, 2019 Stephen P. Martin Northern Illinois University [email protected] 1 Topics: Why: Motivation for supersymmetry (SUSY) • What: SUSY Lagrangians, SUSY breaking and the Minimal • Supersymmetric Standard Model, superpartner decays Who: Sorry, not covered. • For some more details and a slightly better attempt at proper referencing: A supersymmetry primer, hep-ph/9709356, version 7, January 2016 • TASI 2011 lectures notes: two-component fermion notation and • supersymmetry, arXiv:1205.4076. If you find corrections, please do let me know! 2 Lecture 1: Motivation and Introduction to Supersymmetry Motivation: The Hierarchy Problem • Supermultiplets • Particle content of the Minimal Supersymmetric Standard Model • (MSSM) Need for “soft” breaking of supersymmetry • The Wess-Zumino Model • 3 People have cited many reasons why extensions of the Standard Model might involve supersymmetry (SUSY). Some of them are: A possible cold dark matter particle • A light Higgs boson, M = 125 GeV • h Unification of gauge couplings • Mathematical elegance, beauty • ⋆ “What does that even mean? No such thing!” – Some modern pundits ⋆ “We beg to differ.” – Einstein, Dirac, . However, for me, the single compelling reason is: The Hierarchy Problem • 4 An analogy: Coulomb self-energy correction to the electron’s mass A point-like electron would have an infinite classical electrostatic energy. Instead, suppose the electron is a solid sphere of uniform charge density and radius R. An undergraduate problem gives: 3e2 ∆ECoulomb = 20πǫ0R 2 Interpreting this as a correction ∆me = ∆ECoulomb/c to the electron mass: 15 0.86 10− meters m = m + (1 MeV/c2) × .
    [Show full text]
  • Physics with B-Mesons in ATLAS
    Physics with B-mesons in ATLAS Lidia Smirnova1, Alexey Boldyrev, on behalf of the ATLAS Collaboration* *Moscow State University , E-mail: [email protected], [email protected] Abstract B-physics is an important part of studies with the LHC beams at low luminosities. Ef- fective B-meson reconstruction in ATLAS can produce a clean sample of events for detailed physics analysis with first data. The analysis includes measurements of B-meson masses and proper lifetimes to verify the performance of the Inner Detector, and to estimate back- grounds and trigger efficiencies for rare decays. ATL-PHYS-PROC-2009-135 23 November 2009 XXXIX International Symposium on Multiparticle Dynamics 4-9 September 2009 Gomel Region Belarus 1Speaker 1 Introduction B-physics is one of the important fields that can be studied with the first ATLAS data. Until now the in- formation about B-meson production come from B-factories, high-energy electron-positron and electron- proton colliders and proton-antiproton colliders. The proton-proton collisions at the LHC will be the next step in studies of B-meson production in hadron interactions with large b-quark production cross section and high luminosity. The ATLAS experiment will be able to reconstruct exclusive B-meson decays. After the introduction, section two describes briefly the ATLAS detector and triggers, relevant for B- physics, with stress on di-muon channels. Reconstruction of inclusive J=y! mm decays and separation of J=y from direct and indirect (B-hadrons) production mechanisms are discussed. The efficiency of B+-meson reconstruction with B+ ! J=yK+ decay mode is presented.
    [Show full text]
  • JHEP05(2010)010 , 6 − Ing Springer and 10 May 4, 2010 9 : April 19, 2010 − : Tic Inflationary December 3, 2009 : Published Lar Potential, and No S
    Published for SISSA by Springer Received: December 3, 2009 Accepted: April 19, 2010 Published: May 4, 2010 Light inflaton hunter’s guide JHEP05(2010)010 F. Bezrukova and D. Gorbunovb aMax-Planck-Institut f¨ur Kernphysik, P.O. Box 103980, 69029 Heidelberg, Germany bInstitute for Nuclear Research of the Russian Academy of Sciences, 60th October Anniversary prospect 7a, Moscow 117312, Russia E-mail: [email protected], [email protected] Abstract: We study the phenomenology of a realistic version of the chaotic inflationary model, which can be fully and directly explored in particle physics experiments. The inflaton mixes with the Standard Model Higgs boson via the scalar potential, and no additional scales above the electroweak scale are present in the model. The inflaton-to- Higgs coupling is responsible for both reheating in the Early Universe and the inflaton production in particle collisions. We find the allowed range of the light inflaton mass, 270 MeV . mχ . 1.8 GeV, and discuss the ways to find the inflaton. The most promising are two-body kaon and B-meson decays with branching ratios of orders 10−9 and 10−6, respectively. The inflaton is unstable with the lifetime 10−9–10−10 s. The inflaton decays can be searched for in a beam-target experiment, where, depending on the inflaton mass, from several billions to several tenths of millions inflatons can be produced per year with modern high-intensity beams. Keywords: Cosmology of Theories beyond the SM, Rare Decays ArXiv ePrint: 0912.0390 Open Access doi:10.1007/JHEP05(2010)010 Contents 1 Introduction 1 2 The model 3 3 Inflaton decay palette 6 4 Inflaton from hadron decays 10 JHEP05(2010)010 5 Inflaton production in particle collisions 12 6 Limits from direct searches and predictions for forthcoming experiments 14 7 Conclusions 16 A The νMSM extension 16 1 Introduction In this paper we present an example of how (low energy) particle physics experiments can directly probe the inflaton sector (whose dynamics is important at high energies in the very Early Universe).
    [Show full text]
  • 1. Introduction
    EXPERIMENTAL ASPECTS OF B PHYSICS * Persis S. Drell Laboratory of Nuclear Studies Cornell University Ithaca, NY 14853 1. Introduction The first experimental evidence for the existence of the b quark came in 1977 from an experiment at FNAL”’ in which high energy protons were scattered off of hadronic targets. A broad resonance, shown in Fig. 1, was observed in the plot of the invariant mass of muon pairs seen in a double armed spectrometer. The width of the resonance was greater than the energy resolution of the apparatus and the data were interpreted as the three lowest lying quark anti-quark bound states of a new quark flavor: b flavor, which stands for either beauty or bottom. These bb bound states were called the f, Y’, and Y”. When the & bound state, the J/qb, was discovered, it was found simulta- neously in proton-nucleus collisions at Brookhaven IN and at SPEAR’“’ in e+e- collisions. However, it took a year for the e+e- storage ring, DORIS, to confirm the f discovery:’ and it was still 2 years later that the then new e+e- storage ring at Cornell, CESR, also observed the Y(lS), T’(2S), T”(3.57 states and dis- covered a fourth state, T”‘(4S)!“] Both storage rings were easily able to resolve the states of the Upsilon system. Figure 2 shows the observed cross section at CESR versus energy in the Upsilon region, and although the apparent width of the 3 lower lying resonances is due to the machine energy spread, the true width and the leptonic width of the T could be inferred from the peak cross section and the leptonic branching ratio!’ The leptonic width is proportional to the square of the quark charges inside the Upsilon and the b quark was inferred to have charge l/3.
    [Show full text]
  • Does Charged-Pion Decay Violate Conservation of Angular Momentum? Kirk T
    Does Charged-Pion Decay Violate Conservation of Angular Momentum? Kirk T. McDonald Joseph Henry Laboratories, Princeton University, Princeton, NJ 08544 (September 6, 2016, updated November 20, 2016) 1Problem + + Charged-pion decay, such as π → μ νµ, is considered in the Standard Model to involve the annihilation of the constituent quarks, ud¯,oftheπ+ into a virtual W + gauge boson, which + materializes as the final state μ νµ. While the pion is spinless, the W -boson is considered to have spin 1, which appears to violate conservation of angular momentum. What’s going on here?1 2Solution A remarked by Higgs in his Nobel Lecture [3], “... in this model the Goldstone massless (spin- 0) mode became the longitudinal polarization of a massive spin-1 photon, just as Anderson had suggested.” That is, in the Higgs’ mechanism, the Sz =0stateofaW boson is more or less still a spin-0 “particle.” Likewise, Weinberg in his Nobel Lecture [4] stated that: “The missing Goldstone bosons appear instead as helicity zero states of the vector particles, which thereby acquire a mass.” A similar view was given in [5]. References [1] S. Ogawa, On the Universality of the Weak Interaction, Prog. Theor. Phys. 15, 487 (1956), http://physics.princeton.edu/~mcdonald/examples/EP/ogawa_ptp_15_487_56.pdf [2] Y. Tanikawa and S. Watanabe, Fermi Interaction Caused by Intermediary Chiral Boson, Phys. Rev. 113, 1344 (1959), http://physics.princeton.edu/~mcdonald/examples/EP/tanikawa_pr_113_1344_59.pdf [3] P.W. Higgs, Evading the Goldstone Boson,Rev.Mod.Phys.86, 851 (2014), http://physics.princeton.edu/~mcdonald/examples/EP/higgs_rmp_86_851_14.pdf [4] S.
    [Show full text]
  • Introduction to Supersymmetry
    Introduction to Supersymmetry J.W. van Holten NIKHEF Amsterdam NL 1 Relativistic particles a. Energy and momentum The energy and momentum of relativistic particles are related by E2 = p2c2 + m2c4: (1) In covariant notation we define the momentum four-vector E E pµ = (p0; p) = ; p ; p = (p ; p) = − ; p : (2) c µ 0 c The energy-momentum relation (1) can be written as µ 2 2 p pµ + m c = 0; (3) where we have used the Einstein summation convention, which implies automatic summa- tion over repeated indices like µ. Particles can have different masses, spins and charges (electric, color, flavor, ...). The differences are reflected in the various types of fields used to describe the quantum states of the particles. To guarantee the correct energy-momentum relation (1), any free field Φ must satisfy the Klein-Gordon equation 2 − 2@µ@ + m2c2 Φ = ~ @2 − 2r2 + m2c2 Φ = 0: (4) ~ µ c2 t ~ Indeed, a plane wave Φ = φ(k) ei(k·x−!t); (5) satisfies the Klein-Gordon equation if E = ~!; p = ~k: (6) From now on we will use natural units in which ~ = c = 1. In these units we can write the plane-wave fields (5) as Φ = φ(p) eip·x = φ(p) ei(p·x−Et): (7) b. Spin Spin is the intrinsic angular momentum of particles. The word `intrinsic' is to be inter- preted somewhat differently for massive and massless particles. For massive particles it is the angular momentum in the rest-frame of the particles, whilst for massless particles {for which no rest-frame exists{ it is the angular momentum w.r.t.
    [Show full text]
  • B Meson Decays Marina Artuso1, Elisabetta Barberio2 and Sheldon Stone*1
    Review Open Access B meson decays Marina Artuso1, Elisabetta Barberio2 and Sheldon Stone*1 Address: 1Department of Physics, Syracuse University, Syracuse, NY 13244, USA and 2School of Physics, University of Melbourne, Victoria 3010, Australia Email: Marina Artuso - [email protected]; Elisabetta Barberio - [email protected]; Sheldon Stone* - [email protected] * Corresponding author Published: 20 February 2009 Received: 20 February 2009 Accepted: 20 February 2009 PMC Physics A 2009, 3:3 doi:10.1186/1754-0410-3-3 This article is available from: http://www.physmathcentral.com/1754-0410/3/3 © 2009 Stone et al This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/ licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Abstract We discuss the most important Physics thus far extracted from studies of B meson decays. Measurements of the four CP violating angles accessible in B decay are reviewed as well as direct CP violation. A detailed discussion of the measurements of the CKM elements Vcb and Vub from semileptonic decays is given, and the differences between resulting values using inclusive decays versus exclusive decays is discussed. Measurements of "rare" decays are also reviewed. We point out where CP violating and rare decays could lead to observations of physics beyond that of the Standard Model in future experiments. If such physics is found by directly observation of new particles, e.g. in LHC experiments, B decays can play a decisive role in interpreting the nature of these particles.
    [Show full text]
  • Kaons in Flavor Tagged B Meson Decays
    Kaons in Flavor Tagged B Meson Decays by Henric Ivar Cronström A Thesis submitted in conformity with the requirements for the Degree of Doctor of Technology at the University of Lund Elementary Particle Physics Department of Physics University of Lund <&Corrri|kl \i HXCfMiltia OcKfctr Jl, 1MI Kaons in Flavor Tagged B Meson Decays by Henric Ivar Cronström Civilingenjör / Master of Science Lund October 29, 1991 ISBN 91-628-0454-5 Document name LUND UNIVERSITY DOCTORAL DLSSERTATION Department of I'hysics Date of issue Oct 31, 1991 University of Lumi, Sölvcgatan S-223 62 Lund, SWEDEN CODEN: u)NFD6/(NFFL-7066) 1991 Authors) Sponsoring organisation llcnric Ivar Cronström Title and subtitle Kaons in Flavor Tagged B Meson Decays Abstract Using the ARGUS detector at the e e storage ring DORIS II, measurements of multiplicities of pseudoscalar kaons, of K'"'(892) and of ^(1020) in B meson decays have been performed through studies of angular and charge correlations between the above particles and high momentum leptons produced in semileptonic B decays. The method has made it possible to measure the multiplicities separately for B- mesons and anti-B-mesons. The excess of like charge lepton-kaon pairs over opposite charge pairs in semilepto- nic decays was used for estimating the ratio of charmed decays over all decays, and thus also the fraction of charmless decays. A search for an excess of fast neutral kaons from rare B decays was also made. All the results obtained support the assumption that almost all B mesons decay through b -> c transitions into charmed hadrons.
    [Show full text]
  • The Higgs As a Pseudo-Goldstone Boson
    Universidad Autónoma de Madrid Facultad de Ciencias Departamento de Física Teórica The Higgs as a pseudo-Goldstone boson Memoria de Tesis Doctoral realizada por Sara Saa Espina y presentada ante el Departamento de Física Teórica de la Universidad Autónoma de Madrid para la obtención del Título de Doctora en Física Teórica. Tesis Doctoral dirigida por M. Belén Gavela Legazpi, Catedrática del Departamento de Física Teórica de la Universidad Autónoma de Madrid. Madrid, 27 de junio de 2017 Contents Purpose and motivation 1 Objetivo y motivación 4 I Foundations 9 1 The Standard Model (SM) 11 1.1 Gauge fields and fermions 11 1.2 Renormalizability and unitarity 14 2 Symmetry and spontaneous breaking 17 2.1 Symmetry types and breakings 17 2.2 Spontaneous breaking of a global symmetry 18 2.2.1 Goldstone theorem 20 2.2.2 Spontaneous breaking of the chiral symmetry in QCD 21 2.3 Spontaneous breaking of a gauge symmetry 26 3 The Higgs of the SM 29 3.1 The EWSB mechanism 29 3.2 SM Higgs boson phenomenology at the LHC: production and decay 32 3.3 The Higgs boson from experiment 34 3.4 Triviality and Stability 38 4 Having a light Higgs 41 4.1 Naturalness and the “Hierarchy Problem” 41 4.2 Higgsless EWSB 44 4.3 The Higgs as a pseudo-GB 45 II Higgs Effective Field Theory (HEFT) 49 5 Effective Lagrangians 51 5.1 Generalities of EFTs 51 5.2 The Chiral Effective Lagrangian 52 5.3 Including a light Higgs 54 5.4 Linear vs.
    [Show full text]