DOCSLIB.ORG

THE HIGGS, VACUUM STABILITY, and OTHER CONSTRAINTS Matthew Reece Harvard University at the PCTS, April 26, 2013 THIS TALK

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
THE HIGGS, VACUUM STABILITY, and OTHER CONSTRAINTS Matthew Reece Harvard University at the PCTS, April 26, 2013 THIS TALK THE HIGGS, VACUUM STABILITY, AND OTHER CONSTRAINTS Matthew Reece Harvard University at the PCTS, April 26, 2013 THIS TALK First, I’m going to explain some constraints on new physics scenarios that try to significantly alter Higgs properties. The motivation for dwelling on this is diminished given recent CMS updates on diphoton. Then I’ll talk a bit about Higgs vacuum stability in the Standard Model. LHC: WHERE WE STAND I looked over my slides from my PCTS talk almost exactly one year ago and still agree with what I said then: •No hint of strong dynamics. Technicolor, composite Higgs, Randall-Sundrum all look even less plausible than they did pre-Higgs. •Higgs mass puts SUSY in an awkward spot •“Natural SUSY”: the MSSM must be very tuned to fit a 125 GeV Higgs (despite many contrary claims in the literature in the last year). Models beyond the MSSM are typically awkward and/or complicated. •Semi-split SUSY: solve most of the hierarchy problem, put scalars at ~10 to 1000 TeV. Increasingly plausible. •Important to keep looking for small deviations from SM Higgs •Keep looking for naturalness signatures (stops, etc.), but bounds are already becoming very strong... HIGGS PROPERTIES Looking increasingly Standard Model-like as more data comes in. Still room for 30 to 50% (large!) deviations! Let’s say, for instance, thatm ˜ D dominates, and is 1 TeV, with ⌅ =0.1, Mmess = 100 TeV (which is consistent with √F 100 TeV as well), m = 2 TeV, and m = 150 GeV. Then ⇥ Y S we have: Let’s say, for instance, thatm ˜ D dominates, and is 1 TeV, with ⌅ =0.1, Mmess = 100 TeV Let’s say, for instance, thatm ˜ dominates, and is 1 TeV, with ⌅ =0.1, M = 100 TeV (which is consistentD with √F 100 TeV as well), m = 2 TeV,mess and m = 150 GeV. Then 2 2 Y 2 S (which is consistent with √F 100m TeV˜ = as⇥ well),2970m GeVY = 2 TeV, andm mS == 150150 GeV. Then2970 GeV 140 GeV. (2.4) we have: ⇥ S scalar we have: − ⇧ − ⇤ Let’s say, for instance, thatm ˜ D dominates, and is 1 TeV, with ⌅ =0.1, Mmess = 100 TeV ⇥ So, this2 model is easily2 compatible with2 the sort of splittings we’re interested in. (which is consistent with √F 100 TeV as well), mY = 2 TeV,2 and mS =m˜ 150S = GeV.2 2970 Then GeV m2scalar = 150 2970 GeV 140 GeV. (2.4) Let’s say, for instance, thatm ˜ D dominates,⇥ and is 1 TeV, with ⌅ =0m˜.1,S M=mess2970= 100 GeV TeV− mscalar =⇧ 150 2970 GeV −140 GeV. ⇤ (2.4) we have: − ⇧ − ⇤ (which is consistent with √F 100 TeV as well), mY = 2 TeV, and mS = 150 GeV. Then ⇥ ⇥ Let’s say, for instance,So, that thism ˜ D modeldominates,2.2 is Couplings easily and is compatible 1 TeV, to with Gauge⇥⌅ with=0.1, the BosonsMmess sort= of 100 and splittings TeV Gauginos we’re interested in. we have: 2 2 So, this2 model is easily compatible with the sort of splittings we’re interested in. m˜ = 2970 GeV mscalar(which= is150 consistent2970 with GeV√F 140100 GeV TeV. as well), m(2.4)Y = 2 TeV, and mS = 150 GeV. Then S − ⇧ − ⇤⇥ ¯ 2 2 we have:2 Now we will integrate out Y and Y and study the induced couplings of S to gauge bosons. m˜ S = 2970 GeV mscalar = 150 ⇥2.22970 Couplings GeV 2.2140 Couplings toGeV Gauge. Bosons(2.4) to Gauge and Bosons Gauginos and Gauginos So, this model− is easily compatible⇧ with the sort− of splittings⇤ we’re interested in. 2 2 To keep things2 simple, we will assume that the mass of the Y s is dominantly supersymmetric. ⇥ m˜ S = 2970Now GeV we will integratemscalar = ¯ out150 Y 2970and GeVY¯ and140 study GeV. the induced(2.4) couplings of S to gauge bosons. So, this model is easily compatible with the sort of splittingsNow we’re we will− interested integrate in.⇧In out thatY and case,Y and we− expect study the to⇤ induced find an couplings e⇤ective of operatorS to gauge of bosons. the form: 2.2 Couplings to Gauge Bosons and Gauginos ⇥ So, thisTo model keep is easily thingsTo compatible keep simple, things we with will simple, the assume sort of we splittings that will the assume we’re mass interested that of the theY in.s mass is dominantly of the Y s supersymmetric. is dominantly supersymmetric. 2.2 Couplings to Gauge Bosons and Gauginos Now we will integrate out Y and Y¯ and study theIn induced that case, couplingsIn we that expect case, of S to weto find gauge expect an bosons. e⇤ toective find operator an e⇤ective of the operator form:c of the2 form: α Now we will integrate out Y and Y¯ and study the2.2 induced Couplings couplings to Gauge of S Bosonsto gauge and bosons. Gauginos d ⇤SWαW + h.c. (2.5) To keep things simple, we will assume that the mass of the Y s is dominantly supersymmetric.c mY To keep things simple, we will assume that the massNow of we the willY s integrate is dominantly out Y supersymmetric.and Y¯ and study the induced2 couplingsc α of S2 to gauge bosons.α In that case, we expect to find an e⇤ective operator of the form: d ⇤SWαW +dh.c.⇤SWαW + h.c. (2.5) (2.5) In that case, we expect to find an e⇤ective operatorTo keep of the things form: simple, we will assume that the massmY of the Y s ism dominantly supersymmetric. Let’s work out the coe⌃Ycient c and then compute the resulting decays. c 2In that case,α we expect to findHIGGS an e⇤ective LOOP-LEVEL operator of the form: c d ⇤SWαWLet’s+ workh.c. out the coe⌃cientToc computeand then(2.5) compute the coe⌃ thecient, resulting let me decays. try to flesh out JiJi’s statement that it’s related to a md2⇤SW W α + h.c. Let’s work out the(2.5) coe⌃cient c and then compute the resulting decays. Y α c 2 α mY To compute the coe⌃cient,d ⇤SW letW me+ tryh.c. to flesh out JiJi’s statement(2.5) that it’s related to a To computembetaCOUPLINGS function the coeα ⌃ coecient,⌃cient. let me Suppose try to flesh we out have JiJi’s a Lagrangian statement that it’s related to a Let’s work out the coe⌃cient c and then computebeta the resulting function decays. coe⌃cient.Y Suppose we have a Lagrangian Let’s work out the coe⌃cient c and then compute the resulting decays.beta function coe⌃cient. Suppose we have a Lagrangian To compute the coe⌃cient, let me tryLet’s to flesh work out out JiJi’s the coe statement⌃cient c and that then it’s compute related the to resulting a decays. 1 To compute the coe⌃cient, let me try to flesh out JiJi’s statementA lot of interest that it’s in related this when to a both ATLAS1 and CMS a aµ⇧ To compute the coe⌃cient, let me try to flesh out JiJi’s statementa aµ that⇧ it’s related= to a 2 Gµ⇧G . (2.6) beta function coe⌃cient. Suppose we have a Lagrangian = Gµ⇧G . 1 a L aµ⇧−4g (2.6) beta function coe⌃cient. Suppose we have a Lagrangianbeta function coeshowed⌃cient. a Suppose high diphoton we have a rate. Lagrangian Recall:L − Higgs4g2 couplings= to G G . (2.6) photons, gluons related to low-energy theorem.L −4g2 µ⇧ 1 1 a aµ⇧ = a aµG⇧ G . Then in1 facta (2.6)gaµ⇧is a running coupling. In particular, suppose that we have fields at a scale M, = Gµ⇧G2 µ.Then⇧ in fact g is a running= coupling.(2.6)G G In. particular, suppose that we(2.6) have fields at a scale M, L −L4g2 −4g 2 µ⇧ with µ<M<Run fromThen ⇥ in , down so factwith thatL gtois the − µ<M< a4 gwith running beta an function intermediate coupling.⇥, so coe that⌃cient In the particular, changes beta function from supposeb below coe that⌃M wecientto haveb + changes fields∆b at from a scaleb belowM, M to b + ∆b ThenThen in fact in factg is ag runningis a running coupling. coupling. In particular, In particular,Then suppose inabove fact suppose thatg isthresholdM a we. running that Thenwith have we fields coupling.µ<M< taking have at above fields a account In scale particular, ⇥ at M,Mat a so of,.which scale Then that supposeM the threshold, the, taking beta that beta wefunction account function have fields of coe at that a⌃ scalecient threshold,M, changes from b below M to b + ∆b withwithµ<M<µ<M<⇥, so⇥ that, so thethat beta the function beta function coewith⌃cient coeµ<M<⌃ changescientchanges⇥ changes, from soabove thatb frombelow from theM beta .b M Thenbelow toto function b + takingM ∆ coeto b . ⌃b accountcient+ ∆b changes of that from b threshold,below M to b + ∆b 1 1 b ⇥ ∆b ⇥ aboveaboveM. ThenM. Then taking taking account account of that of threshold, that threshold,above M. Then taking account of that threshold,= + log +1 log 1 . b ⇥ ∆(2.7)b ⇥ RG: g2(µ) g2(⇥) 1 8⌃2 1µ 8⌃2b= M⇥ +∆b log⇥ + log . (2.7) 1 1 b ⇥ ∆b ⇥ 1 1 b ⇥ ∆b = ⇥ g2(+µ) logg2(⇥)+ 8⌃2log µ. 8⌃2 M (2.7) 1 1 b ⇥ ∆b ⇥2 = 2 + 2 log +2 2 log 2.
Load more

Recommended publications
  • Search Strategies for New Physics at the Lhc A
    SEARCH STRATEGIES FOR NEW PHYSICS AT THE LHC A DISSERTATION SUBMITTED TO THE DEPARTMENT OF PHYSICS AND THE COMMITTEE ON GRADUATE STUDIES OF STANFORD UNIVERSITY IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY Daniele Spier Moreira Alves August 2011 © 2011 by Daniele Spier Moreira Alves. All Rights Reserved. Re-distributed by Stanford University under license with the author. This work is licensed under a Creative Commons Attribution- Noncommercial 3.0 United States License. http://creativecommons.org/licenses/by-nc/3.0/us/ This dissertation is online at: http://purl.stanford.edu/vr734zr1770 ii I certify that I have read this dissertation and that, in my opinion, it is fully adequate in scope and quality as a dissertation for the degree of Doctor of Philosophy. Jay Wacker, Primary Adviser I certify that I have read this dissertation and that, in my opinion, it is fully adequate in scope and quality as a dissertation for the degree of Doctor of Philosophy. Renata Kallosh, Co-Adviser I certify that I have read this dissertation and that, in my opinion, it is fully adequate in scope and quality as a dissertation for the degree of Doctor of Philosophy. Risa Wechsler Approved for the Stanford University Committee on Graduate Studies. Patricia J. Gumport, Vice Provost Graduate Education This signature page was generated electronically upon submission of this dissertation in electronic format. An original signed hard copy of the signature page is on file in University Archives. iii Preface The LHC is in the frontline of experimental searches for New Physics beyond the Stan- dard Model of Particle Physics.
    [Show full text]
  • A Supersymmetry Primer
    hep-ph/9709356 version 7, January 2016 A Supersymmetry Primer Stephen P. Martin Department of Physics, Northern Illinois University, DeKalb IL 60115 I provide a pedagogical introduction to supersymmetry. The level of discussion is aimed at readers who are familiar with the Standard Model and quantum field theory, but who have had little or no prior exposure to supersymmetry. Topics covered include: motiva- tions for supersymmetry, the construction of supersymmetric Lagrangians, superspace and superfields, soft supersymmetry-breaking interactions, the Minimal Supersymmetric Standard Model (MSSM), R-parity and its consequences, the origins of supersymmetry breaking, the mass spectrum of the MSSM, decays of supersymmetric particles, experi- mental signals for supersymmetry, and some extensions of the minimal framework. Contents 1 Introduction 3 2 Interlude: Notations and Conventions 13 3 Supersymmetric Lagrangians 17 3.1 The simplest supersymmetric model: a free chiral supermultiplet ............. 18 3.2 Interactions of chiral supermultiplets . ................ 22 3.3 Lagrangians for gauge supermultiplets . .............. 25 3.4 Supersymmetric gauge interactions . ............. 26 3.5 Summary: How to build a supersymmetricmodel . ............ 28 4 Superspace and superfields 30 4.1 Supercoordinates, general superfields, and superspace differentiation and integration . 31 4.2 Supersymmetry transformations the superspace way . ................ 33 4.3 Chiral covariant derivatives . ............ 35 4.4 Chiralsuperfields................................ ........ 37 arXiv:hep-ph/9709356v7 27 Jan 2016 4.5 Vectorsuperfields................................ ........ 38 4.6 How to make a Lagrangian in superspace . .......... 40 4.7 Superspace Lagrangians for chiral supermultiplets . ................... 41 4.8 Superspace Lagrangians for Abelian gauge theory . ................ 43 4.9 Superspace Lagrangians for general gauge theories . ................. 46 4.10 Non-renormalizable supersymmetric Lagrangians . .................. 49 4.11 R symmetries........................................
    [Show full text]
  • Probing the BSM Physics with CMB Precision Cosmology: an Application
    Published for SISSA by Springer Received: January 31, 2018 Accepted: February 8, 2018 Published: February 20, 2018 Probing the BSM physics with CMB precision cosmology: an application to supersymmetry JHEP02(2018)118 Ioannis Dalianisa and Yuki Watanabeb aPhysics Division, National Technical University of Athens, 15780 Zografou Campus, Athens, Greece bDepartment of Physics, National Institute of Technology, Gunma College, Gunma 371-8530, Japan E-mail: [email protected], [email protected] Abstract: The cosmic history before the BBN is highly determined by the physics that operates beyond the Standard Model (BSM) of particle physics and it is poorly constrained observationally. Ongoing and future precision measurements of the CMB observables can provide us with significant information about the pre-BBN era and hence possibly test the cosmological predictions of different BSM scenarios. Supersymmetry is a particularly mo- tivated BSM theory and it is often the case that different superymmetry breaking schemes require different cosmic histories with specific reheating temperatures or low entropy pro- duction in order to be cosmologically viable. In this paper we quantify the effects of the possible alternative cosmic histories on the ns and r CMB observables assuming a generic non-thermal stage after cosmic inflation. We analyze TeV and especially multi-TeV super- symmetry breaking schemes assuming the neutralino and gravitino dark matter scenarios. We complement our analysis considering the Starobinsky R2 inflation model to exemplify the improved CMB predictions that a unified description of the early universe cosmic evo- lution yields. Our analysis underlines the importance of the CMB precision measurements that can be viewed, to some extend, as complementary to the laboratory experimental searches for supersymmetry or other BSM theories.
    [Show full text]
  • Supersplit Supersymmetry and the 750 Gev Diphoton Excess
    Supersplit Supersymmetry and the 750 GeV Diphoton Excess Kyle Cranmer1 1Center for Cosmology and Particle Physics, Dept. of Physics, New York University, New York , NY 10003 (Dated: April 1, 2016) We examine the scenario of “supersplit supersymmetry” in light of the observed diphoton excess at 750 GeV. We discuss the difficulties of explaining tuning of the model with anthropic arguments alone and propose a new phenothropic principle. A brief statistical analysis of the model is conducted including the 2-dimensional look-elsewhere effect in two of the model parameters most relevant for LHC phenomenology. We find that the model is excluded by both ATLAS and CMS at the 2 − 3σ level; however, the excess can be accommodated by invoking the phenothropic selection mechanism with a small overall contribution to the tuning of the theory. I. INTRODUCTION SUSY Split SUSY Supersplit SUSY Mpl q,u˜ ˜ ,d,l,e˜ ˜ ˜, h˜ ,h˜ , g˜ The ATLAS and CMS collaborations have recently re- u d i h 2 ported an excess in the diphoton invariant mass spectrum at 750 GeV in both of the 8 and 13 TeV data sets [1, 2]. The possibility that this is the new physics holy grail we have been seeking has sent the theoretical community ˜ ˜ Mi q,u˜ ˜ ,d,l,e, h 2 into a frenzy [3]. We will refer to this putative particle with the Greek letter digamma ̥ [29]. Of course, the discovery\ of the Higgs boson at 125 GeV brought to the forefront the issue of naturalness and fine Mw q,u,d,l,e, h ,h , g q,u,d,l,e, h ,h˜ , h ˜ , q,u,d,l,e, h , g tuning [4, 5].
    [Show full text]
  • The Quantum Structure of Space and Time
    QcEntwn Structure &pace and Time This page intentionally left blank Proceedings of the 23rd Solvay Conference on Physics Brussels, Belgium 1 - 3 December 2005 The Quantum Structure of Space and Time EDITORS DAVID GROSS Kavli Institute. University of California. Santa Barbara. USA MARC HENNEAUX Universite Libre de Bruxelles & International Solvay Institutes. Belgium ALEXANDER SEVRIN Vrije Universiteit Brussel & International Solvay Institutes. Belgium \b World Scientific NEW JERSEY LONOON * SINGAPORE BElJlNG * SHANGHAI HONG KONG TAIPEI * CHENNAI Published by World Scientific Publishing Co. Re. Ltd. 5 Toh Tuck Link, Singapore 596224 USA ofJice: 27 Warren Street, Suite 401-402, Hackensack, NJ 07601 UK ofice; 57 Shelton Street, Covent Garden, London WC2H 9HE British Library Cataloguing-in-PublicationData A catalogue record for this hook is available from the British Library. THE QUANTUM STRUCTURE OF SPACE AND TIME Proceedings of the 23rd Solvay Conference on Physics Copyright 0 2007 by World Scientific Publishing Co. Pte. Ltd. All rights reserved. This book, or parts thereoi may not be reproduced in any form or by any means, electronic or mechanical, including photocopying, recording or any information storage and retrieval system now known or to be invented, without written permission from the Publisher. For photocopying of material in this volume, please pay a copying fee through the Copyright Clearance Center, Inc., 222 Rosewood Drive, Danvers, MA 01923, USA. In this case permission to photocopy is not required from the publisher. ISBN 981-256-952-9 ISBN 981-256-953-7 (phk) Printed in Singapore by World Scientific Printers (S) Pte Ltd The International Solvay Institutes Board of Directors Members Mr.
    [Show full text]
  • Goldstone Gauginos
    week ending PRL 115, 161801 (2015) PHYSICAL REVIEW LETTERS 16 OCTOBER 2015 Goldstone Gauginos † ‡ Daniele S. M. Alves,1,2,* Jamison Galloway,1, Matthew McCullough,3, and Neal Weiner1,§ 1Center for Cosmology and Particle Physics, Department of Physics, New York University, New York, New York 10003, USA 2Department of Physics, Princeton University, Princeton, New Jersey 08544, USA 3Theory Division, CERN, 1211 Geneva 23, Switzerland (Received 10 April 2015; published 14 October 2015) Models of supersymmetry with Dirac gauginos provide an attractive scenario for physics beyond the standard model. The “supersoft” radiative corrections and suppressed supersymmetry production at colliders provide for more natural theories and an understanding of why no new states have been seen. Unfortunately, these models are handicapped by a tachyon which is naturally present in existing models of Dirac gauginos. We argue that this tachyon is absent, with the phenomenological successes of the model preserved, if the right-handed gaugino is a (pseudo-)Goldstone field of a spontaneously broken anomalous flavor symmetry. DOI: 10.1103/PhysRevLett.115.161801 PACS numbers: 12.60.Jv The results of LHC7 and LHC8 have directly challenged corrections that are “supersoft,” in that they are cut off the idea that the weak scale is natural. The quadratic without any divergences. The squark mass is then naturally divergences of the Higgs mass associated with the top a factor of ∼4–5 below the gluino mass, where the Yukawa coupling, the Higgs’ gauge interactions, and its contributions to the Higgs soft masses are cut off, and self-interactions all should be cut off not too far above the the logarithmic enhancement is minimal [7].
    [Show full text]
  • Supersymmetry David Morrissey March 2, 2016
    Notes #2: Supersymmetry David Morrissey March 2, 2016 Supersymmetry (SUSY) is the most popular proposal for new physics beyond the SM. For every known particle, SUSY predicts that there exists a superpartner particle with the same charge but with spin differing by half a unit. The most attractive feature of SUSY is that it can resolve the electroweak hierarchy problem by inducing cancellations in the quantum corrections to the Higgs mass parameter. SUSY can also provide a dark matter candidate and account for the baryon asymmetry, it appears to lead to a unification of the SM gauge couplings close to the Planck scale, and it is an essential component in many attempts to construct a quantum theory of gravity. For these many reasons, SUSY is promising possibility for BSM physics and it is being searched for enthusiastically at the LHC. To illustrate how SUSY addresses the electroweak hierarchy problem, suppose there exists a new fermion Ψ together with its superpartner boson Ψ, both with a coupling yΨ to the Higgs field. The equality of this coupling is enforced by supersymmetry. Together, the net leading quantum correction to the Higgs quadratic parametere for this particle-superpartner pair is 2 2 yΨ 2 2 ∆µ Me Me . (1) ≃ (4π)2 Ψ − Ψ This correction is acceptably small, ∆µ2 . µ2, provided the masses of the particle and its superpartner are not too different. Numerically, we have µ 100 GeV, so if SUSY is to address the hierarchy problem the superpartners of the SM part∼icles should not be too much e heavier than MΨ .
    [Show full text]
  • Chirality, Particle Physics, and “Theory Space”
    Chirality, particle physics, and “theory space” Erich Poppitz oronto From a theorists’ point of view, much effort in particle physics today evolves around chirality, chiral symmetry, and its breaking... Lord Kelvin’s definition (1904) (first observed by Pasteur, 1848) “I call any geometrical figure, or group of points, chiral, and say it has chirality, if its image in a plane mirror, ideally realized, cannot be brought to coincide by itself.” χειρ = hand chirality = “handedness” The difference between objects with left- or right- handedness is common in the macroscopic world. e.g., we metabolize only right-handed glucose Alice to Kitty: “...Perhaps looking-glass milk isn’t good to drink....” In the microscopic world of elementary particles and the fundamental forces between them, however, the symmetry between L-(eft) and R-(ight) holds almost universally. the four fundamental forces: - gravity the one most relevant for - electromagnetism macroscopic world - weak interactions (chemistry/biology) - strong interactions are blind to “chirality” - except the weak interactions Lee, Yang (theory, 1956) Wu (experiment, 1957) spin-polarized Cobalt Nickel + electron+ anti-neutrino 27 protons 28 protons 33 neutrons 32 neutrons spinning nucleus mirror in the mirror the nuclei rotate in the opposite direction symmetry with mirror image would require equal number of electrons going up and down spin-polarized Cobalt Nickel + electron+ anti-neutrino 27 protons 28 protons 33 neutrons 32 neutrons spinning nucleus mirror in the mirror the nuclei rotate in the opposite direction symmetry with mirror image would require equal number of electrons going up and down but this is not what was found! Wu (experiment, 1957) thus, weak interactions are “chiral” Wu’s discovery led Gell-Mann (1958) to postulate the chiral (“V-A”) structure of weak interactions, and ultimately, led to the establishment of the Standard Model of particle physics of Glashow, Salam, Weinberg (~1970).
    [Show full text]
  • Hadronic Production and Decays of Charginos and Neutralinos in Split
    KIAS 05036 Hadronic production and decays of Charginos and Neutralinos in Split Supersymmetry Kingman Cheung Department of Physics and NCTS, National Tsing Hua University, Hsinchu, Taiwan, R.O.C. Jeonghyeon Song Department of Physics, Konkuk University, Seoul 143-701, Korea (Dated: December 25, 2018) Abstract In the scenario recently proposed by Arkani-Hamed and Dimopoulos, the supersymmetric scalar particles are all very heavy, at least of the order of 109 GeV but the gauginos, higgsino, and one of the CP-even neutral Higgs bosons remain light under a TeV. In addition to gluino production, the first SUSY signature would be pair production of neutralinos and/or charginos. Here we study, with explicit CP violation, the production of neutralinos and charginos at hadronic colliders as well as the possible decay modes. We notice that the branching ratio of the neutralino radiative decay can be sizable unlike the case with light sfermions. In particular, the decay of χ0 χ0γ 3 → 1 has a branching ratio of the order O(1) percent. In colliders, it would give rise to signatures of an e e isolated single photon plus missing energy. arXiv:hep-ph/0507113v2 1 Sep 2005 PACS numbers: 12.60.Jv, 14.80.Ly, 13.87.Fh 1 I. INTRODUCTION Supersymmetry (SUSY) is one of the most elegant solutions, if not the best, to the gauge hierarchy problem. It also provides a dynamical mechanism for electroweak symmetry breaking, as well as a viable candidate for dark matter (DM). Conventional wisdom tells us that SUSY must exist at the TeV scale, otherwise the fine tuning problem returns.
    [Show full text]
  • Identifying Jet Substructure with N-Subjesseness
    Identifying JeT Substructure with N-subJesseness Cari Cesarotti Department of Physics, Harvard University, Cambridge, MA, 02138 April 1, 2021 Abstract We introduce a novel observable|N-subJesseness|with the purpose of identifying and char- acterizing JeT substructure. This observable is empirically derived from studying the ParTonic composition of high-quality JeTs. In this work we demonstrate not only the strong correla- tion between large N-subJesseness and SM JeTs, but also the potential for discriminating JeTs from various NP samples. We study how several substructure observables can be combined to improve the classification of diverse physics scenarios. 1 Introduction Detection of new physics (NP) at the Large Hadron Collider (LHC) has proved elusive [1]. This does not necessarily imply that there is no remaining possibility for discovery at the LHC, but instead suggests that NP may be hiding in previously unexplored regimes of event topology. A robust approach to discovering new physics is therefore to design searches without strong model dependence, that are sensitive to only generic characteristics of NP models. A potentially lucrative and recently revisited highly clever strategy [2{4] is then to develop tools that measure event characteristics that are fundamentally distinct from the Standard Model (SM). The event topology of Quantum Chromodynamics (QCD) at the collider scale is characterized by its small 't Hooft coupling, therefore we primarily observe two- or three-jet events. NP events may have similar or distinct substructure; we can conceive of scenarios with strongly coupled (large 't Hooft coupling) dynamics at TeV scales that don't form jets, or models with collimated cascades of complicated decays that produce similar radiation patterns.
    [Show full text]
  • Higgs-Mass Predictions in the MSSM and Beyond
    Eur. Phys. J. C (2021) 81:450 https://doi.org/10.1140/epjc/s10052-021-09198-2 Review Higgs-mass predictions in the MSSM and beyond P. Slavich 1,a, S. Heinemeyer2,3,4, E. Bagnaschi5,H.Bahl6, M. Goodsell1, H. E. Haber7,T.Hahn8, R. Harlander9, W. Hollik8,G.Lee10,11,12, M. Mühlleitner13, S. Paßehr9, H. Rzehak14, D. Stöckinger15, A. Voigt16, C. E. M. Wagner17,18,19, G. Weiglein6, B. C. Allanach20,T.Biekötter6,S.Borowka21, J. Braathen6, M. Carena18,19,22, T. N. Dao23, G. Degrassi24, F. Domingo25, P. Drechsel6, U. Ellwanger26, M. Gabelmann13, R. Gröber27, J. Klappert9, T. Kwasnitza15, D. Meuser6,L.Mihaila28,N.Murphy29,K.Nickel25, W. Porod30,E.A.ReyesRojas31, I. Sobolev6, F. Staub13 1 Laboratoire de Physique Théorique et Hautes Énergies, LPTHE, Sorbonne Université, CNRS, 75005 Paris, France 2 Instituto de Física Teórica, (UAM/CSIC), Universidad Autónoma de Madrid, Cantoblanco, 28049 Madrid, Spain 3 Campus of International Excellence UAM+CSIC, Cantoblanco, 28049 Madrid, Spain 4 Instituto de Física de Cantabria (CSIC-UC), 39005 Santander, Spain 5 Paul Scherrer Institut, 5232 Villigen, Switzerland 6 DESY, Notkestraße 85, 22607 Hamburg, Germany 7 Santa Cruz Institute for Particle Physics, University of California, Santa Cruz, CA 95064, USA 8 Max-Planck Institut für Physik, 80805 Munich, Germany 9 Institute for Theoretical Particle Physics and Cosmology, RWTH Aachen University, 52074 Aachen, Germany 10 Department of Physics, Korea University, Seoul 136-713, Korea 11 Department of Physics, LEPP, Cornell University, Ithaca, NY 14853, USA 12 Department
    [Show full text]
  • Supersplit Supersymmetry
    SLAC-PUB-11125 hep-th/0503249 Supersplit Supersymmetry Patrick J. Fox,1 David E. Kaplan,2 Emanuel Katz,3, 4 Erich Poppitz,5 Veronica Sanz,6 Martin Schmaltz,4 Matthew D. Schwartz,7 and Neal Weiner8 1Santa Cruz Institute for Particle Physics, Santa Cruz, CA, 95064 2Dept. of Physics and Astronomy, Johns Hopkins University, Baltimore, MD 21218 3Stanford Linear Accelerator Center, 2575 Sand Hill Rd. Menlo Park, CA 94309 4Dept. of Physics, Boston University, Boston, MA 02215 5Department of Physics, University of Toronto, 60 St George St, Toronto, ON M5S 1A7, Canada 6Universitat de Granada, Campus de Fuentenueva, Granada, Spain 7University of California, Dept. of Physics, Berkeley, CA 94720-7300 8Center for Cosmology and Particle Physics, Dept. of Physics, New York University, New York , NY 10003 (Dated: April 1, 2005) The possible existence of an exponentially large number of vacua in string theory behooves one to consider possibilities beyond our traditional notions of naturalness. Such an approach to electroweak physics was recently used in “Split Supersymmetry”, a model which shares some successes and cures some ills of traditional weak-scale supersymmetry by raising the masses of scalar superpartners significantly above a TeV. Here we suggest an extension - we raise, in addition to the scalars, the gaugino and higgsino masses to much higher scales. In addition to maintaining many of the successes of Split Supersymmetry - electroweak precision, flavor-changing neutral currents and CP violation, dimension-4 and 5 proton decay - the model also allows for natural Planck-scale supersymmetry breaking, solves the gluino-decay problem, and resolves the coincidence problem with respect to gaugino and Higgs masses.
    [Show full text]