DOCSLIB.ORG

Supersplit Supersymmetry and the 750 Gev Diphoton Excess

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read 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]. The arrival of the ̥ motivates reexami- u d i 1 u d 1 i g , g˜ nation of finely tuned theories. Let us briefly revisit the ˜ ˜ ˜ i i q,u˜ ˜ ,d,l,e˜ ˜, hu ,h d , g˜ i history and motivation of this paradigm. The realization that the broad string landscape may have an exponen- FIG. 1: Mass scales in the MSSM, split SUSY and supersplit tially large number of metastable vacua [6–8] supported SUSY. Taken from Ref. [12]. Weinberg’s anthropic argument for a solution to the cos- mological constant problem based upon a scan over many possible universes [9]. Agrawal et. al [10] and later The addition of the ̥ changes this picture and once Arkani-Hamed and Dimopoulos [11] argued that similar again pulls us back into the era in which the phenomeno- scanning may be relevant for weak scale physics. In “split logical consequences of additional fields must be studied. supersymmetry”, all but one scalar of the many scalars As was highlighted by Ref. [13] it is difficult to accommo- in the minimal supersymmetric standard model (MSSM) date additional scalars and address naturalness without are given very large masses. One linear combination of resorting to awkward mechanisms. On the other hand, the two scalar superpartners of the Higgsinos remains while the so-called “atomic principle” [10] has been used light and then acquires a vacuum expectation value (vev) as part of an anthropic argument for fine tuning of the which breaks electroweak symmetry and gives masses to weak scale, this does not carry over to the unexpected the weak gauge bosons. The fermion masses, which can ̥ resonance. Thus, we seek a new principle that can be protected by symmetries, remain small. address this additional source of tuning. Fox, et. al. [12] took the next logical extension by decoupling both Higgsinos and the gauginos in a model they call “supersplit supersymmetry”. The low energy II. THE PHENOTHROPIC PRINCIPLE effective theory consists of SU(3) SU(2) U(1) gauge fields and three generations of quarks× and leptons,× as well Already in Ref. [12], Fox, et. al. argued that the exis- as one scalar (whose mass is tuned to be light) which tence of fine tuning in nature dramatically increases the is responsible for electroweak symmetry breaking. The time scale over which fundamental physical laws are dis- Lagrangian for this model is simply covered. Since the rapid discovery of fundamental laws is 1 µν 1 µν 1 µν strongly correlated with the advance of technologies that = 2 Wµν W 2 Bµν B 2 Gµν G L −4g1 − 4g2 − 4gs might lead to the destruction of civilization, this should ∗ + ψ¯ (iγµD m )ψ + D hDµh V (h) (1) be taken into account in the Drake equation. In short, a f µ − f f µ − universe without fine-tuning, theoretical physics may not where f indexes the various fermions, and D is the ap- be possible. [30] propriate covariant derivative. The spectrum of split and Here we consider a variant of this idea. Instead of the supersplit supersymmetry are shown in Fig. 1. ill-defined notion of “theoretical physics”, we employ a 2 more quantitative measure, namely the number of pa- 100 pers submitted to the arXiv. Recently, a quantitative 9.6 model for the number of papers covering an unexpected 8.4 result was proposed [16]. In particular, the number of 80 papers as a function of time was derived from a com- 7.2 pounded Poisson process leading to a di-gamma function 60 6.0 Pl µN (T ) [31]. /M 4.8 ˜ Next we follow the logic of the anthropic principle, q 40 which can schematically be written using Bayes theorem M 3.6 as 2.4 20 p(universe us) p(us universe ) p(universe) . (2) 1.2 | ∝ | 0.0 |anthropic{z selection} 20 40 60 80 100 Mh /MPl We highlight the term p(us universe ) that is the mech- 2 anism for anthropic selection.| By analogy we introduce FIG. 2: Plot of q(Mh , Mq˜)= −2 ln λ(Mh , Mq˜). the phenothropic principle, which can schematically be 2 2 written p(excess papers) p(papers excess ) p(excess) . (3) is that the prior degree of belief in this unexpected res- | ∝ | onance is low, the risk associated to a false discovery is phenothropic| {z selection} high, and the time needed to collect enough data to make a more conclusive statement is short. The term p(papers excess ) is a new selection mechanism | Another issue that comes up in the statistical analy- addressed by Ref. [16], while p(excess) is the subject of sis of ̥ is that the data prefer a wide resonance. This more traditional statistical analysis and the following sec- leads to a look-elsewhere effect in both the mass and tion. width of the resonance. We briefly review the methodol- ogy used by ATLAS as described in a beautiful work by III. STATISTICAL CONSIDERATIONS Vitells and Gross [21]. In this formalism we have a likeli- hood function of the form L(µ,ν1,ν2) where µ is a signal strength parameter proportional to σ Br and ν1,ν2 are The ATLAS and CMS collaborations have quantified the unknown mass and width of the× new particle. Next the statistical significance of the excess in the mγγ spec- one performs the search by scanning over ν1 and ν2 and trum under a both spin-0 and spin-2 hypotheses. The calculating the test statistic [22] local significance for the 13 TeV data under the spin- 0 hypothesis stands at 3.9σ and 2.9σ, for ATLAS and maxθ L(µ =0,ν1,ν2,θ) q(ν1,ν2)= 2 log (4) CMS respectively. Of course, we do not know the mass of − maxµ,θ L(µ,ν1,ν2,θ) the resonance a priori, so one must correct for the look- elsewhere effect [17]. After this correction, the global The LEE correction in this case is based on significance for ATLAS is around 2σ and even less for 2 −u/2 CMS. While a heuristic approach would be to say that E[φ(Au)] = P (χ1 >u)+ e (N1 + √uN2) (5) one experiment tells you where too look, and the other provides the statistical evidence. This approach violates where Au is the ’excursion set above level u (eg. the set an obvious permutation symmetry and has been criti- of parameter points in (ν1,ν2) that have a q(ν1,ν2) >u), cized recently [18]. A more careful treatment would be φ(Au) is the Euler characteristic of the excursion set, to combine first and then correct for the look-elsewhere E[φ(Au)] is the expectation of the Euler characteristic 2 effect on the combination (see Ref. [19] for more details). of those excursion sets under the null, P (χ1 > u) is the While the objection to the heuristic approach is a good standard chi-square probability , and N1 and N2 are two one in principle, in this particular case it does not make coefficients that characterize the chi-square random field. a very large quantitative difference. Now we repeat, for the first time, this 2-d LEE correc- Perhaps more interesting is the issue of the 5σ discov- tion for a new physics model description of the ̥ excess. ery threshold. As discussed in Cousins’s tome on the Instead of scanning over the mass and width of a generic Jeffreys-Lindley Paradox (see the section on the mythol- spin-0 or spin-2 particle, we scan over two high-scale pa- ogy of 5σ) the arbitrary 5σ convention was adopted as rameters of the supersplit supersymmetry model. We an ad hoc way of protecting against the look-elsewhere perform this scan for many pairs of the model parame- effect [20]. To use 5σ threshold after correcting for the ters. Figure 2 shows the scan with respect to Mh2 and look-elsewhere effect is both arbitrary and breaking from Mq˜.
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]
  • 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]
  • LHC Phenomenology
    LHC Phenomenology Heather Logan Carleton University 31st Symposium on Physics in Collision Vancouver, Canada, 28 Aug{1 Sep, 2011 1 Outline Introduction: why we expect new discoveries at the LHC Higgs constraints and phenomenology Frameworks for physics beyond the Standard Model I: Supersymmetry Frameworks for physics beyond the Standard Model II: Composite models Summary and outlook Heather Logan (Carleton U.) LHC Phenomenology Physics In Collision 2011 2 The Standard Model is extremely successful so far. Can't we get by with just the degrees of freedom that we've observed? - 3 generations of quarks; CKM matrix for flavor physics - 3 generations of charged leptons - Neutrinos with mass (might need something new there) - gluons from SU(3) strong interaction - photon plus massive W and Z from SU(2) U(1) ± × (Electroweak symmetry is broken, but do we really have to worry about how?) - (Dark matter?) - (How to bring gravity into the quantum theory?) Heather Logan (Carleton U.) LHC Phenomenology Physics In Collision 2011 3 The Standard Model is extremely successful so far. Can't we get by with just the degrees of freedom that we've observed? - 3 generations of quarks; CKM matrix for flavor physics - 3 generations of charged leptons - Neutrinos with mass (might need something new there) - gluons from SU(3) strong interaction - photon plus massive W and Z from SU(2) U(1) ± × (Electroweak symmetry is broken, but do we really have to worry about how?) - (Dark matter?) - (How to bring gravity into the quantum theory?) The answer is no: the SM without a Higgs is intrinsically incomplete.
    [Show full text]