Anomalous Anomalous Scaling?

Total Page:16

File Type:pdf, Size:1020Kb

Anomalous Anomalous Scaling? Physics Letters B 668 (2008) 312–314 Contents lists available at ScienceDirect Physics Letters B www.elsevier.com/locate/physletb Anomalous anomalous scaling? ∗ Alessandro Strumia a, ,NikolaosTetradisb a Dipartimento di Fisica dell’Università di Pisa and INFN, Pisa, Italy b Department of Physics, University of Athens, Zographou GR-15784, Athens, Greece article info abstract Article history: Motivated by speculations about infrared deviations from the standard behavior of local quantum field Received 15 May 2008 theories, we explore the possibility that such effects might show up as an anomalous running of coupling Received in revised form 9 August 2008 constants. The most sensitive probes are presently given by the anomalous magnetic moments of the Accepted 28 August 2008 electron and the muon, that suggest that α runs 1.00047 ± 0.00018 times faster than predicted by the Available online 3 September 2008 em Standard Model. The running of and up to the weak scale is confirmed with a precision at the % Editor: G.F. Giudice αem αs level. © 2008 Elsevier B.V. All rights reserved. 1. Introduction 2. Speculations The above ideas about a non-local connection between the IR and UV cutoffs do not have a very precise meaning, and one can The range of validity of Quantum Field Theory (QFT) may be debate whether they would lead to any of the effects mentioned limited not only in the UltraViolet (UV), E Λ ,butalsointhe UV above. Rather than arguing in any one direction, we present the InfraRed (IR), E Λ ≡ 1/L, with a non-trivial connection be- IR uncertain issues. tween Λ and Λ . This possibility has attracted interest due to UV IR Firstly, when do these non-local phenomena appear in particle the following reasons. physics? The weakest possibility is only when strong gravity effects, On the theoretical side, requiring that the entropy associ- such as those arising from black holes, are directly relevant. This ated with the QFT degrees of freedom ∼ (Λ /Λ )3 saturates UV IR would practically mean never, as black hole phenomena (Hawk- the Bekenstein entropy [1] ∼ L2 M2 of a black hole with size Pl ing radiation, etc.) are quantitatively irrelevant in all processes we L leads to ∼ 3 M2 . Alternatively, it has been suggested ΛIR ΛUV/ Pl can realistically observe (possibly unless the true quantum gravity that one should require that systems whose size L exceeds their scale is much below MPl). The strongest possibility is that states Schwarzschild radius ∼ m/M2 do not appear in QFT. For m ∼ Pl with energy E ΛUV that propagate for more than L do not exist 3 3 ∼ 2 ΛUV L , this requirement leads to ΛIR ΛUV/MPl [2]. and must be dropped from QFT. However, this possibility seems to On the phenomenological side, Refs. [2,3] discussed possible contradict experience. We see TeV γ rays from the galactic center, connections of these ideas with the cosmological constant and the particles with energies up to 1020 eV from extragalactic sources, supersymmetry breaking puzzles. Indeed, in standard QFT the val- etc. ues of the vacuum energy, scalar masses squared and dimension- We envisage a scenario in which the bulk of the contributions less couplings are given by their bare Planck-scale values plus a from (real of virtual) modes to quantities such as the energy den- 4 2 quantum correction proportional to ΛUV, ΛUV and ln ΛUV,respec- sity or the renormalized couplings is delimited by a scale that tively. Such non-local effects could change this power-counting, depends on the IR cutoff. Individual very energetic modes may still solving or modifying the hierarchy problems associated with mas- exist, but their effect on the above observables is negligible. For ex- sive parameters [2,3]. ample, one may limit the temperature T of a system of size L by We observe here that dimensionless couplings may be similarly demanding that this system does not collapse into a black hole: affected, leading to an anomalous Renormalization Group (RG) run- 2 T MPl/L. States with energy much larger than this limit may ning, and we study how accurately present data test the standard exist, but their contribution to the energy density is negligible. Our QFT prediction. basic, and possibly contentious, assumption is that gravity enforces a similar constraint to the contributions from virtual fluctuations. This leads to limits on the energy density, the quantum-corrected vacuum energy density (i.e. the minimum of the potential) [2],the * Corresponding author. Higgs mass (i.e. the curvature of the potential at its minimum) [3], E-mail address: [email protected] (A. Strumia). and possibly all couplings (i.e. the derivatives of the potential). The 0370-2693/$ – see front matter © 2008 Elsevier B.V. All rights reserved. doi:10.1016/j.physletb.2008.08.061 A. Strumia, N. Tetradis / Physics Letters B 668 (2008) 312–314 313 smallness of the cosmological constant is consistent with such an By using the β function of Eq. (3) within the dimensional reg- assumption. ularization formalism, we get for the one-loop RG running of a Secondly, what is the precise meaning of ΛIR? There are various gauge coupling α possibilities, and we mention two: (i) The IR cutoff can be defined − 1 1 μ1 δ by imposing boundary conditions such that QFT lives “in a box” − β ln +···. (4) 1−δ with size 1/ΛIR. (ii) ΛIR is the minimal energy scale that appears α(μ ) α(μ) μ in loop integrations. In practical cases these choices can lead to This is equivalent to the standard expression, with the Minimal − different answers. For example, only in the first case the IR cutoff Subtraction mass scale μ replaced by μ1 δ. In theories with sev- for the cosmological constant would√ be the Hubble distance 1/H eral particle masses and sizable RG corrections, the factor δ gener- ∼ ∼ (possibly leading to a small ΛUV MPl H eV [2]). On the other ically can become some unknown function of the energy. In order hand, H does not appear in the one-loop correction to the vacuum to compute it, we would need to know the physics around ΛUV. energy, equal to the value of the potential V at its physical local In the next sections, we explore the most sensitive experimen- minimum tal probes of anomalous RG running, assuming for definiteness that ΛUV all Standard Model formula get modified as in Eq. (2), with a con- 4 1 d k 2 stant δ to be extracted from data. V V bare + Str ln k + V , (1) 2 (2π)4 bare Λ IR 3. Running of αem from me to mμ unless ΛIR = H is imposed. The measurements of the anomalous magnetic moments of the We finally arrive to the third issue: what is the precise meaning of electron [4] ΛUV if it is viewed as a function of ΛIR? As we explained above, we as- sume that Λ sets the upper limit for the bulk of the fluctuations UV g /2 = 1.00115965218085(76) (5) that renormalize a quantum field theory. Modes with characteristic e momenta above ΛUV may exist, but they do not contribute signif- and of the muon [5] icantly to the renormalization of the couplings. According to this logic ΛUV (ΛIR) may be used as the upper bound of the momen- gμ/2 = 1.00116592080(63), (6) tum integration is expressions such as (1). together with the assumption of the validity of the Standard If the quantum correction to the minimum of V is naturally Model, allow us to infer the electromagnetic coupling α (μ) at small thanks to an anomalous dependence of Λ on Λ [2],one em UV IR the scales μ = m and m ,inviewofthetheoreticalprediction expects a similar anomalous running of the whole potential, and in e μ particular of its coupling constants. In standard QFT, the one-loop g = 2 + α (m )/π +···, (7) corrections to any dimensionless coupling (e.g. the gauge boson i em i vertex g) has the form where ··· denotes higher-order effects. We recall that ge gives the most precise determination of αem, that is consistent with lower- 3 2 gbare ΛUV energy probes from atomic physics [4]. Assuming the anomalous g(p) = gbare − β ln + finite , (2) 8π p2 running where p is some combination of the external momenta that sets 1 1 1 − δ mμ − = ln +··· (8) the IR cutoff in the loop integration. In standard QFT the physical αem(me) αem(mμ) 3π me coupling g(p) ‘runs’ with the energy p of the process, and the RG one gets the presently most precise determination of δ: coefficient β is a number that depends on the particle content of the theory above p.(InEq.(2) we assumed that all the masses are δ =−(0.047 ± 0.018)%. (9) negligibly small.) If, instead, non-QFT effects produce some physical UV cutoff The central value of δ is about 3σ below zero, because, for δ = 0, ∼ − SM = ± ΛUV that depends on ΛIR p, one generically obtains an anoma- gμ is about 3σ above the SM prediction, (gμ gμ )/2 (23 − lous RG running of g(p). For example, in the one-loop approxima- 9) × 10 10 , with the precise number depending on how one deals tion the running is proportional to with the theoretical uncertainties on higher-order QCD corrections − + to gμ:relyingone e data and/or on τ -decay data [5]. ∂ ln ΛUV β → β 1 − ≡ β(1 − δ). (3) The usual new-physics interpretation of the gμ − 2 anomaly is ∂ ln ΛIR that new particles with heavy mass M, like supersymmetric parti- ∼ 2 2 The correction appears because fewer UV modes contribute to cles, affect gμ giving an extra contribution gμ α2mμ/M .They quantum corrections when the IR cutoff is lowered.
Recommended publications
  • Measurement of Associated Z+Charm Production and Search for W' Bosons in the CMS Experimented at the LHC
    UNIVERSIDAD COMPLUTENSE DE MADRID FACULTAD DE CIENCIAS FÍSICAS Departamento de Física Atómica, Molecular y Nuclear TESIS DOCTORAL Measurement of associated Z+charm production and search for W' bosons in the CMS experimented at the LHC Medida de la producción asociada de Z+charm y búsqueda de bosones W' en el experimento CMS del LHC MEMORIA PARA OPTAR AL GRADO DE DOCTOR PRESENTADA POR Alberto Escalante del Valle Director Juan Alcaraz Maestre Madrid, 2017 ©Alberto Escalante del Valle, 2017 CENTRO DE INVESTIGACIONES ENERGETICAS´ MEDIOAMBIENTALES Y TECNOLOGICAS´ Measurement of associated Z+charm production and Search for W0 bosons in the CMS experiment at the LHC by Alberto Escalante del Valle A thesis submitted in partial fulfillment for the degree of Doctor of Philosophy in the Universidad Complutense de Madrid Facultad de Ciencias F´ısicas Departamento de F´ısicaAt´omica,Molecular y Nuclear Supervised by: Dr. Juan Alcaraz Maestre Dr. Juan Pablo Fern´andezRamos Madrid February 2017 CENTRO DE INVESTIGACIONES ENERGETICAS´ MEDIOAMBIENTALES Y TECNOLOGICAS´ Medida de la producci´onasociada de Z+charm y B´usquedade bosones W0 en el experimento CMS del LHC por Alberto Escalante del Valle Memoria de la tesis presentada para optar al grado de Doctor en Filosof´ıa en la Universidad Complutense de Madrid Facultad de Ciencias F´ısicas Departamento de F´ısicaAt´omica,Molecular y Nuclear Supervisado por: Dr. Juan Alcaraz Maestre Dr. Juan Pablo Fern´andezRamos Madrid Febrero 2017 Abstract Measurement of associated Z+charm production and Search for W0 bosons in the CMS experiment at the LHC by Alberto Escalante del Valle Do we understand how elementary particles interact with each other? Are we able to predict the result of the collisions of these elementary particles at the LHC? The objective of this thesis is to investigate the validity of our current theoretical model, the Standard Model of particle physics, to explain the production of two low rate processes in proton-proton collisions at the LHC.
    [Show full text]
  • Jhep06(2019)110
    Published for SISSA by Springer Received: February 22, 2019 Revised: June 3, 2019 Accepted: June 10, 2019 Published: June 20, 2019 Coset cosmology JHEP06(2019)110 Luca Di Luzio,a;b Michele Redi,c Alessandro Strumiaa and Daniele Teresia;b aDipartimento di Fisica, Universit`adi Pisa, Largo Pontecorvo 3, I-56127 Pisa, Italy bINFN, Sezione di Pisa, Largo Pontecorvo 3, I-56127 Pisa, Italy cINFN Sezione di Firenze, Via G. Sansone 1, I-50019 Sesto Fiorentino, Italy E-mail: [email protected], [email protected], [email protected], [email protected] Abstract: We show that the potential of Nambu-Goldstone bosons can have two or more local minima e.g. at antipodal positions in the vacuum manifold. This happens in many models of composite Higgs and of composite Dark Matter. Trigonometric potentials lead to unusual features, such as symmetry non-restoration at high temperature. In some mod- els, such as the minimal SO(5)=SO(4) composite Higgs with fermions in the fundamental representation, the two minima are degenerate giving cosmological domain-wall problems. Otherwise, an unusual cosmology arises, that can lead to supermassive primordial black holes; to vacuum or thermal decays; to a high-temperature phase of broken SU(2)L, pos- sibly interesting for baryogenesis. Keywords: Cosmology of Theories beyond the SM, Global Symmetries, Spontaneous Symmetry Breaking, Technicolor and Composite Models ArXiv ePrint: 1902.05933 Open Access, c The Authors. https://doi.org/10.1007/JHEP06(2019)110 Article funded by SCOAP3. Contents
    [Show full text]
  • Phenomenological Implications of Neutrinos in Extra Dimensions
    October 27, 2018 CERN-TH/2001–184 hep-ph/0107156 IFUP–TH/18–2001 Phenomenological implications of neutrinos in extra dimensions Andr´ede Gouvˆea, Gian Francesco Giudice, Alessandro Strumia∗, and Kazuhiro Tobe Theoretical Physics Division, CERN, CH-1211, Gen`eve 23, Switzerland Abstract Standard Model singlet neutrinos propagating in extra dimensions induce small Dirac neutrino masses. While it seems rather unlikely that their Kaluza-Klein excitations directly participate in the observed neutrino oscillations, their virtual exchange may lead to detectable signatures in future neutrino experiments and in rare charged lepton processes. We show how these effects can be described by specific dimension-six effective operators and discuss their experimental signals. 1 Introduction The hypothesis that Standard Model (SM) singlet fields propagate in extra dimensions leads to striking arXiv:hep-ph/0107156v2 1 Nov 2001 results. When applied to the graviton, it allows to lower the quantum gravity scale down to few TeV [1, 2], suggesting a new scenario for addressing the Higgs mass hierarchy problem. It is also natural to consider the case of “right-handed neutrinos” (i.e., fermions without SM gauge interactions) propagating in extra dimensions. The smallness of the neutrino masses, of the Dirac type, could in fact be a manifestation of this hypothesis [3, 4, 5, 6]. If the radius of the compactified dimensions is very large, R > eV−1, Kaluza-Klein (KK) modes of right-handed neutrinos would significantly participate in neutrino∼ oscillations. However, KK interpreta- tions of the atmospheric and solar neutrino puzzles are disfavoured by the following arguments: A KK tower of sterile neutrinos gives rise to active/sterile oscillations at a small ∆m2 1/R2 • ∼ only in the case of a single large extra dimension.
    [Show full text]
  • Higgs Inflation
    Higgs inflation Javier Rubio Institut fur¨ Theoretische Physik, Ruprecht-Karls-Universitat¨ Heidelberg, Philosophenweg 16, 69120 Heidelberg, Germany —————————————————————————————————————————— Abstract The properties of the recently discovered Higgs boson together with the absence of new physics at collider experiments allows us to speculate about consistently extending the Standard Model of particle physics all the way up to the Planck scale. In this context, the Standard Model Higgs non- minimally coupled to gravity could be responsible for the symmetry properties of the Universe at large scales and for the generation of the primordial spectrum of curvature perturbations seeding structure formation. We overview the minimalistic Higgs inflation scenario, its predictions, open issues and extensions and discuss its interplay with the possible metastability of the Standard Model vacuum. —————————————————————————————————————————— arXiv:1807.02376v3 [hep-ph] 13 Mar 2019 Email: [email protected] 1 Contents 1 Introduction and summary3 2 General framework7 2.1 Induced gravity . .7 2.2 Higgs inflation from approximate scale invariance . .8 2.3 Tree-level inflationary predictions . 11 3 Effective field theory interpretation 14 3.1 The cutoff scale . 14 3.2 Relation between high- and low-energy parameters . 16 3.3 Potential scenarios and inflationary predictions . 17 3.4 Vacuum metastability and high-temperature effects . 21 4 Variations and extensions 22 4.1 Palatini Higgs inflation . 23 4.2 Higgs-Dilaton model . 24 5 Concluding remarks 26 6 Acknowledgments 26 2 1 Introduction and summary Inflation is nowadays a well-established paradigm [1–6] able to explain the flatness, homogene- ity and isotropy of the Universe and the generation of the primordial density fluctuations seeding structure formation [7–10].
    [Show full text]
  • Astrophysics and Physics of Neutrino Detection
    Astrophysics and Physics of Neutrino Detection A THESIS SUBMITTED TO THE FACULTY OF THE GRADUATE SCHOOL OF THE UNIVERSITY OF MINNESOTA BY Cheng-Hsien Li IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF Doctor of Philosophy Professor Yong-Zhong Qian, Advisor September, 2017 c Cheng-Hsien Li 2017 ALL RIGHTS RESERVED Acknowledgements This dissertation would be impossible to complete without the help and support from many people and institutions. First and foremost, I would like to express my sincere gratitude to my research advisor, Professor Yong-Zhong Qian, who has patiently guided me through this long PhD journey. I learned a lot from his insights in neutrino physics and his approaches to problems during countless hours of discussion. He always offered helpful suggestions regarding my thesis projects and how to conduct rigorous research. I would like to thank Dr. Projjwal Banerjee for guiding me on the SN1987A project presented in this thesis. He was not only a research collaborator but he is also a dear friend to me. He kindly offered advice and encouragement which helped me overcome difficulties during my PhD study. In addition, I feel grateful to have received a lot of help from then fellow graduate students, Dr. Ke-Jun Chen, Dr. Meng-Ru Wu, Dr. Zhen Yuan, Mr. Zhu Li, and Mr. Zewei Xiong, in the Nuclear Physics Group. I am also indebted to Professor Hans-Thomas Janka and Professor Tobias Fischer for generously providing supernova simulation results from their research groups upon request, Professor Huaiyu Duan for commenting on my wave-packet project, and Professor Alexander Heger for the computing resource I received in the research group.
    [Show full text]
  • Indirect Searches in the PAMELA and Fermi Era Aldo Morselli, Igor Moskalenko
    Indirect searches in the PAMELA and Fermi era Aldo Morselli INFN, Sezione di Roma Tor Vergata Springel, Wang, Volgensberger, Ludlow, Jenkins, Helmi, Navarro, Frenk & White ‘08 New Horizons for Modern Cosmology, Dark Matter, February 9, 2009, Galileo Instiute, Firen Aldo Morselli, INFN Roma Tor Vergata 1 PAMELA: Cosmic-Ray Antiparticle Measurements: Antiprotons an example in mSUGRA 5 years simulation fd: Clumpiness factors needed to disentangle a neutralino induced component in the antiproton flux f = the dark matter fraction concentrated in clumps d = the overdensity due to a clump with respect to the local halo density A.Lionetto, A.Morselli, V.Zdravkovic JCAP09(2005)010 [astro-ph/0502406] New Horizons for Modern Cosmology, Dark Matter, February 9, 2009, Galileo Instiute, Firen Aldo Morselli, INFN Roma Tor Vergata 2 Supersymmetry introduces free parameters: In the MSSM, with Grand Unification assumptions, the masses and couplings of the SUSY particles as well as their production cross sections, are entirely described once 5 parameters are fixed: • M1/2 the mass parameter of supersymmetric partners of gauge fields (gauginos) • µ the higgs mixing parameters that appears in the neutralino and chargino mass matrices • m0 the common mass for scalar fermions at the GUT scale • A the trilinear coupling in the Higgs sector • tang β = v2 / v1 = <H2> / <H1> the ratio between the two vacuum expectation values of the Higgs fields New Horizons for Modern Cosmology, Dark Matter, February 9, 2009, Galileo Instiute, Firen Aldo Morselli, INFN Roma Tor Vergata
    [Show full text]
  • Sterile Neutrinos in 4D and 5D in Supernovæ and the Cosmo
    Scuola Normale Superiore Sterile Neutrinos in 4D and 5D in Supernovæ and the Cosmo Marco Cirelli Advisors Dr. Andrea Romanino Prof. Riccardo Barbieri Ph.D. Thesis Autumn 2003 A Anna Contents Preface iii Rationale 1 1 Introduction: New Particle Physics from Astrophysics and Cosmology 3 1.1 TheStandardModelandwhytogobeyond . ......... 3 1.1.1 TheHierarchyProblem . ..... 5 1.1.2 Introduction to Extra Dimensions . ......... 7 1.2 “Standard” neutrino physics and why to go beyond . .............. 11 1.2.1 “Whatisleft,whatisnext?” . ....... 13 1.2.2 Sterileneutrinos .............................. ...... 15 1.3 TheroleofSupernovæ.............................. ....... 18 1.3.1 Supernova basics and neutrino signal formation . .............. 18 1.3.2 Theenergylossconstraint. ........ 21 1.3.3 Waitingforthenextsupernova . ........ 23 1.4 TheroleoftheEarlyUniverse . ......... 27 1.4.1 Big Bang Nucleosynthesis . ....... 27 1.4.2 Large Scale Structure and Cosmic Microwave Background............. 35 2 A (4D) sterile neutrino 38 2.1 Active-sterile neutrino mixing formalism . ................ 38 2.2 Sterile effects in cosmology . .......... 41 2.2.1 Technicaldetails .............................. ...... 41 2.2.2 Results ....................................... 45 2.3 SterileeffectsinSupernovæ . .......... 48 2.3.1 Technicaldetails .............................. ...... 50 2.3.2 Results ....................................... 54 3 Neutrinos in Extra Dimensions 56 3.1 Theextradimensionalsetup. .......... 57 3.2 Cosmological safety (or irrelevance) . ............... 58 i 3.3 Supernovacoreevolution . ......... 58 3.3.1 Thefeedbackmechanisms . ...... 59 3.3.2 Details of the model of core evolution . .......... 60 3.4 Theoutcome: boundsandsignals. .......... 70 3.5 Appendix: subleading invisible channels . ............... 76 4 Conclusions 77 References 79 ii Preface During my Ph.D. course, under the guidance of Riccardo Barbieri and Andrea Romanino, I began work- ing on fascinating subjects at the intersection of High Energy Physics, Neutrino Physics, Astrophysics and Cosmology.
    [Show full text]
  • Pos (EPS-HEP2011) 098 Neutrino Mass Models at the Tev Scale
    Neutrino mass models at the TeV scale and their PoS(EPS-HEP2011)098 tests at the LHC Alessandro Strumia∗ Dipartimento di Fisica dell’Università di Pisa and INFN, Italia National Institute of Chemical Physics and Biophysics, Ravala 10, Tallinn, Estonia E-mail: [email protected] Assuming that the new particles introduced by type-I, type-II, type-III see-saw in order to mediate neutrino masses are below a TeV, we describe their resulting manifestations at LHC. The 2011 Europhysics Conference on High Energy Physics-HEP 2011, July 21-27, 2011 Grenoble, Rhône-Alpes France ∗Speaker. c Copyright owned by the author(s) under the terms of the Creative Commons Attribution-NonCommercial-ShareAlike Licence. http://pos.sissa.it/ Neutrino mass models at LHC Alessandro Strumia HH HH L H Singlet Triplet Triplet LL LL L H Figure 1: The neutrino Majorana mass operator (LH)2 can be mediated by tree level exchange of: I) a fermion singlet (‘see-saw’); II) a fermion triplet; III) a scalar triplet. PoS(EPS-HEP2011)098 1. See-saw models In the past decade we observed violations of lepton flavor in neutrinos and understood that it is due to neutrino oscillations due to neutrino masses [1]. Neutrino masses can be of Majorana type (violating also lepton number) or of Dirac type (adding to the SM a light right-handed neutrino, such that lepton number is conserved). We here stick to the most plausible scenario for neutrino masses: the see-saw models, all de- signed to give at tree level Majorana masses described by the unique dimension-5 effective operator 2 2 (LH) =2LL.
    [Show full text]
  • Jhep06(2010)036
    Published for SISSA by Springer Received: April 6, 2010 Accepted: May 25, 2010 Published: June 8, 2010 JHEP06(2010)036 Thermal production of axino dark matter Alessandro Strumia CERN, PH-TH, CH-1211, Geneva 23, Switzerland Dipartimento di Fisica dell’Universit`adi Pisa, Largo Pontecorvo 3, 56127, Pisa, Italia INFN { Sezione di Pisa, Largo Pontecorvo 3, 56127, Pisa, Italia E-mail: [email protected] Abstract: We reconsider thermal production of axinos in the early universe, adding: a) missed terms in the axino interaction; b) production via gluon decays kinematically allowed by thermal masses; c) a precise modeling of reheating. We find an axino abunance a few times larger than previous computations. Keywords: Supersymmetry Phenomenology ArXiv ePrint: 1003.5847 Open Access doi:10.1007/JHEP06(2010)036 Contents 1 Introduction1 2 Axino couplings2 3 Thermal axino production rate2 JHEP06(2010)036 4 Thermal axino abundance5 5 Conclusions6 1 Introduction The strong CP problem can be solved by the Peccei-Quinn symmetry [1], that manifests 9 at low energy as a light axion a with a decay constant f >∼ 5 10 GeV [2]. In supersym- metric models the axion a gets extended into an axion supermultiplet which also contains the scalar saxion s and the fermionic axinoa ~ [3{5]. Depending on the model of super- symmetry breaking, the axino can easily be lighter than all other sparticles, becoming the stable lightest supersymmetric particle (LSP) and consequently a Dark Matter candidate (warm axino: [6]; hot axino: [7]; cold axino: [8]; [9]). It is thereby interesting to compute its cosmological abundance.
    [Show full text]
  • KEK-PH2018 Timetable
    KEK-PH2018 Timetable Tuesday, 13 February 2018 09:00 - 09:30 Registration 09:30 - 10:30 Talks Convener: Mihoko Nojiri (KEK) 09:30 Late-time magnetogenesis 30' Speaker: Kiwoon Choi (CTPU, IBS) 10:00 Lovely phase space 30' Speaker: Tom Melia (Kavli IPMU) 10:30 - 11:00 Tea Time 11:00 - 12:00 Talks Convener: Alejandro Ibarra (Technical University of Munich) 11:00 Axion coupled to hidden sector 30' Speaker: Fuminobu Takahashi (Tohoku University) 11:30 Multi-Messenger Astrophysics in the Gravitational Wave Era 30' Speaker: Kunihito Ioka (YITP, Kyoto University) 12:00 - 13:30 Lunch 13:30 - 15:30 Joint Session with Muon g-2 Workshop Convener: Bradley Lee Roberts (Boston University) Location: Kobayashi Hall, Kenkyu-honkan 13:30 Belle II overview 30' Speaker: Phillip Urquijo (University of Melbourne) 14:00 Fermilab muon g-2 experiment 30' Speaker: Sudeshna Ganguly (University of Illinois at Urbana-Champaign) 14:30 J-PARC muon g-2 experiment 30' Speaker: Takayuki Yamazaki (KEK) 15:00 New Physics and the Muon g-2 30' Speaker: Hooman Davoudiasl (Brookhaven National Laboratory) 15:30 - 15:50 Tea Time 15:50 - 17:30 Short Talks Convener: Fuminobu Takahashi (Tohoku University) 15:50 High-energy neutrinos from multi-body decaying dark matter 20' Speaker: Nagisa Hiroshima (KEK, ICRR) 16:10 Search for New physics with High multiplicity from High energy cosmic rays 20' Speaker: Yongsoo Jho (Yonsei University) 16:30 Thermal Gravitational Contribution to Dark Matter Production 20' Speaker: Yong Tang (University of Tokyo) 16:50 Enhanced Axion-Photon Coupling
    [Show full text]
  • Publications 2008- 2009
    Publications 2008- 2009 Inter-team papers – in refereed journals 1. Model-independent implications of the e+-, anti-proton cosmic ray spectra on properties of Dark Matter Marco Cirelli (Saclay, SPhT), Mario Kadastik, Martti Raidal (NICPB, Tallinn), Alessandro Strumia (Pisa U. & INFN, Pisa) . Sep 2008. 25pp. Published in Nucl.Phys.B813:1-21,2009. e-Print: arXiv:0809.2409 [hep-ph]* Cited 141 times 2. Non-linear isocurvature perturbations and non-Gaussianities David Langlois, Filippo Vernizzi, David Wands (includes UniverseNet members from Saclay + APC Paris). Sep 2008. 24pp. Published in JCAP 0812:004,2008. e-Print: arXiv:0809.4646 [astro-ph] Cited 13 times 3. The Effective Theory of Quintessence: the w<-1 Side Unveiled Paolo Creminelli, Guido D'Amico, Jorge Norena, Filippo Vernizzi (includes UniverseNet members from Saclay + ICTP Trieste). Nov 2008. 34pp. Published in JCAP 0902:018,2009. e-Print: arXiv:0811.0827 [astro-ph] Cited 8 times 4. Parameterizing the effect of dark energy perturbations on the growth of structures. Guillermo Ballesteros (Madrid, IFT & CERN), Antonio Riotto (CERN & INFN, Padua). Jul 2008. Published in Phys.Lett.B668:171-176,2008. e-Print: arXiv:0807.3343 [astro-ph]* Cited 11 times 5. Exact Spherically symmetric solutions in massive gravity. Z. Berezhiani (L'Aquila U. & Gran Sasso), D. Comelli (INFN, Ferrara), F. Nesti, L. Pilo (L'Aquila U. & Gran Sasso) . Mar 2008. 20pp. Published in JHEP 0807:130,2008. e-Print: arXiv:0803.1687 [hep-th]* Cited 10 times 6. Precision studies of the NNLO DGLAP evolution at the LHC with CANDIA. Alessandro Cafarella (Democritos Nucl. Res. Ctr.), Claudio Coriano (Salento U.
    [Show full text]
  • Grand Unification at the Electroweak Scale
    Large Extra Dimensions & Grand Unification at the Electroweak Scale Behrad Taghavi Department of Physics & Astronomy, Stony Brook University. ! Advisor: Dr. Patric Meade OUTLINE • Motivations • Kaluza-Klein Theory • Localization on Topological Defects • Large Extra Dimensions Paradigm • ADD Model • Hierarchy Problem • Proton Stability • Other Models (eg. UED) • References 2 MOTIVATIONS We need beyond standard model theories to answer questions like hierarchy problem, unification of all fundamental forces, etc. Most of beyond standard model theories (like String Theory, M Theory, GUTs, MSSM, etc.) predict unification of forces at the energy scale close to planck mass. Large Extra Dimensions paradigm is capable of answering most of unanswered questions in SM elegantly and also keeps high energy physics as a experiment-based field of physics. 3 KALUZA-KLEIN THEORY Kaluza–Klein theory (KK theory) is a unified field theory of gravitation and electromagnetism built around the idea of a fifth dimension beyond the usual 4 of space and time. “Kaluza-Klein” mechanism has been first introduced in the 1921 paper of “Theodor Kaluza” , which extended classical GR to 4+1 dimensions that resulted in unification of Electromagnetism and Einstein’s Gravity. In 1926, “Oskar Klein” gave Kaluza's classical 5-dimensional theory a quantum interpretation by introduction of “curled up” or “compact” dimensions. 4 KALUZA-KLEIN THEORY Assume that the world is (4+ n )-dimensional (n 1 ), but the extra ≥ dimensions are compact. If n =1 , our world is a M 4 S 1 manifold. ! ⌦ All fields are defined on this “M 4 S 1 cylinder”. ⌦ ! For a scalar field Φ ( x µ ,Z ) single-valuedness condition reads: Φ(xµ,Z)=Φ(xµ,Z+2⇡R),µ=0, 1, 2, 3.
    [Show full text]