Search

We explore the sparticle mass spectra including LSP dark matter within the framework of supersymmetric $SU(4)_c \times SU(2)_L \times SU(2)_R$ (422) models, taking into account the constraints from extensive LHC and cold dark matter searches. The soft supersymmetry-breaking parameters at $M_{GUT}$ can be non-universal, but consistent with the 422 symmetry. We identify a variety of coannihilation scenarios compatible with LSP dark matter, and study the implications for future supersymmetry searches and the ongoing muon g-2 experiment., 21 pages, 8 figs

We present $\psi'$MSSM, a model based on a $U(1)_{\psi'}$ extension of the minimal supersymmetric standard model. The gauge symmetry $U(1)_{\psi'}$, also known as $U(1)_N$, is a linear combination of the $U(1)_\chi$ and $U(1)_\psi$ subgroups of $E_6$. The model predicts the existence of three sterile neutrinos with masses $\lesssim 0.1~{\rm eV}$, if the $U(1)_{\psi'}$ breaking scale is of order 10 TeV. Their contribution to the effective number of neutrinos at nucleosynthesis is $\Delta N_{\nu}\simeq 0.29$. The model can provide a variety of possible cold dark matter candidates including the lightest sterile sneutrino. If the $U(1)_{\psi'}$ breaking scale is increased to $10^3~{\rm TeV}$, the sterile neutrinos, which are stable on account of a $Z_2$ symmetry, become viable warm dark matter candidates. The observed value of the standard model Higgs boson mass can be obtained with relatively light stop quarks thanks to the D-term contribution from $U(1)_{\psi'}$. The model predicts diquark and diphoton resonances which may be found at an updated LHC. The well-known $\mu$ problem is resolved and the observed baryon asymmetry of the universe can be generated via leptogenesis. The breaking of $U(1)_{\psi'}$ produces superconducting strings that may be present in our galaxy. A $U(1)$ R symmetry plays a key role in keeping the proton stable and providing the light sterile neutrinos., Comment: 10 pages including 6 figures, uses Revtex, version published in Phys. Rev. D

Inspired by the 750 GeV diphoton state recently reported by ATLAS and CMS, we propose a U(1)_{B-L} extension of the MSSM which predicts the existence of four spin zero resonance states that are degenerate in mass in the supersymmetric limit. Vector-like fields, a gauge singlet field, as well as the MSSM Higgsinos are prevented from acquiring arbitrary large masses by a U(1) R-symmetry. Indeed, these masses can be considerably lighter than the Z' gauge boson mass. Depending on kinematics the resonance states could decay into right handed neutrinos and sneutrinos, and/or MSSM Higgs fields and Higgsinos with total decay widths in the multi-GeV range., 5 pages including 2 figures, uses Revtex, version published in Physical Review D

This report, prepared for the Community Planning Study - Snowmass 2013 - summarizes the theoretical motivations and the experimental efforts to search for baryon number violation, focussing on nucleon decay and neutron-antineutron oscillations. Present and future nucleon decay search experiments using large underground detectors, as well as planned neutron-antineutron oscillation search experiments with free neutron beams are highlighted., Comment: Report of the Community Summer Study (Snowmass 2013), Intensity Frontier -- Baryon Number Violation Group

52 p.; International audience; This report summarizes the work of the Energy Frontier Higgs Boson working group of the 2013 Community Summer Study (Snowmass). We identify the key elements of a precision Higgs physics program and document the physics potential of future experimental facilities as elucidated during the Snowmass study. We study Higgs couplings to gauge boson and fermion pairs, double Higgs production for the Higgs self-coupling, its quantum numbers and $C\!P$-mixing in Higgs couplings, the Higgs mass and total width, and prospects for direct searches for additional Higgs bosons in extensions of the Standard Model. Our report includes projections of measurement capabilities from detailed studies of the Compact Linear Collider (CLIC), a Gamma-Gamma Collider, the International Linear Collider (ILC), the Large Hadron Collider High-Luminosity Upgrade (HL-LHC), Very Large Hadron Colliders up to 100 TeV (VLHC), a Muon Collider, and a Triple-Large Electron Positron Collider (TLEP).

The Proceedings of the 2011 workshop on Fundamental Physics at the Intensity Frontier. Science opportunities at the intensity frontier are identified and described in the areas of heavy quarks, charged leptons, neutrinos, proton decay, new light weakly-coupled particles, and nucleons, nuclei, and atoms., Comment: 229 pages

A gauged U(1)_B-L symmetry predicts three right handed handed neutrinos and its spontaneous breaking automatically yields the seesaw mechanism. In a supersymmetric setting this breaking can be nicely linked with inflation to yield deltaT/ T proportional to (M_B-L / M_P)^2, where M_B-L (M_P) denote the B-L breaking (Planck) scale. Thus M_B-L is estimated to be of order 10^16 GeV, and the heaviest right handed neutrino mass is less than or of order 10^14 GeV. A second right handed neutrino turns out to have a mass of order 10-10^2 T_r, where T_r (=0.97. The tensor to scalar ratio r is negligible, and dn_s/dlnk, Comment: Based on talks given by Q. Shafi at Planck 03, 11th International Workshop on Neutrino Telescopes, and PASCOS 2005. 9 pages, 8 figures

Contents of Part 1: 1. Status of the Standard Model(P.H. Frampton), 2. Cosmological Constraints from MBA and Polarization (A. Melchiorri), 3. AdS/CFT Correspondence and Unification at About 4 TeV (P.H. Frampton), 4. New Solutions in String Field Theory (L. Bonora), 5. The Approach Unifying Spins and Charges (A. Borstnik Bracic and N. Mankoc Borstnik) 6. An Example ... (N. Mankoc Borstnik and H.B. Nielsen) 7. Hierarchy Problem and a New Bound State (C.D. Froggatt and H.B. Nielsen) 8. What Comes Next? (Q. Shafi) 9. Loops Versus Strings (E. Alvarez) 10. Fuzzy Two-dimensional Spaces (F. Lizzi) (Contents of Part 2: 11. Supersymmetric Grandunification and Fermion Masses (B. Bajc) 12. General Principles of Brane Kinematics and Dynamics (M. Pavsic) 13. Cosmological Neutrinos (G. Mangano) 14. The Problem of Mass (C.D. Froggatt) 15. How to Approach Quantum Gravity ... (D. Grumiller and W. Kummer) 16. Hidden Spacetime Symmetries and Generalized Holonomy in M-theory (M.J. Duff and J.T. Liu) 17. On the Resolution of Space-Time Singularities II (M. Maceda and J. Madore) 18. The Multiple Point Principle (D.L. Bennett and H.B. Nielsen) 19. Dynamics of Glue-Balls in N = 1 SYM Theory (L. Bergamin) 20. Quantization of Systems with Continuous Symmetries ... (M.V. Chichikina) 21. Singular Compactifications and Cosmology (L. Jaerv, T. Mohaupt and F. Saueressig) 22. Fundamental Physics and Lorentz Violation (R. Lehnert) 23. Functional Approach to Squeezed States ... (L. Musongela) 24. Constraining the Curvaton Scenario (M. Postma) 25. D-Branes and Unitarity of Noncommutative Field Theories (A. Torrielli) 26. Spinorial Cohomology and Supersymmetry (D. Tsimpis)), Comment: Contains articles by different authors presented at the EURESCO organized 'Euroconference on Symmetries Beyond the Standard Model', 12. - 17. July 2003, Portoroz, Slovenia. Editors were N. Mankoc Borstnik, H. Bech Nielsen, C.D. Froggatt, D. Lukman. Part 1 of 2 (both parts printed as one volume). viii+137pp

We discuss a calculable version of brane inflation, in which a set of parallel D-brane and anti-D-brane worlds, initially displaced in extra dimension, slowly attract each other. In the effective four-dimensional theory this slow motion of branes translates into a slow-roll of a scalar field (proportional to their separation) with a flat potential that drives inflation. The number of possible e-foldings is severely constrained. The scalar spectral index is found to be 0.97, while the effective compactification scale is of order $10^{12}$ GeV. Reheating of the Universe is provided by collision and subsequent annihilation of branes., Comment: Talk given by Q.S. at the workshop in Heidelberg (April 4-7, 2001), and at the EURESCO conference in Le Londe (France) May 11-16, 2001. 12pp

We present a minimal string-inspired supersymmetric $SU(4) \times SU(2)_L \times SU(2)_R$ model, and provide a detailed analysis of the symmetry breaking potential in this model, based on a generalisation of that recently proposed by Dvali, Lazarides and Shafi. The model contains a global U(1) R-symmetry and reduces to the MSSM at low energies. However it improves on the MSSM since it explains the magnitude of its $\mu$ term and gives a prediction for $\tan \beta \simeq m_t/m_b$. It also predicts an essentially stable proton, and contains both `cold' and `hot' dark matter candidates. A period of hybrid inflation above the symmetry breaking scale is also possible in this model. Finally it suggests the existence of `heavy' charge $\pm e/6$ (colored) and $\pm e/2$ (color singlet) states., Comment: 13 pages, Latex

We present a solution of the mu problem within a supersymmetric model based on the SU(2)_L x SU(2)_R x U(1)_{B-L} gauge group. We show that this solution implies a built-in hybrid inflationary scenario, which may result in a successful baryogenesis via leptogenesis. Baryon number is essentially conserved as a result of an R-symmetry. Neutrinos with mass in the eV range can provide the `hot' dark matter component., Comment: 11 pages, LaTeX, RevTeX, no figs

In a supersymmetric left-right symmetric model, inflation, baryogenesis (via leptogenesis) and neutrino oscillations can become closely linked. A familiar ansatz for the neutrino Dirac masses and mixing of the two heaviest families, together with the MSW resolution of the solar neutrino puzzle, imply that 1 eV, 10 pages RevTeX 3 eps figures. email: vlachos@physics.auth.gr

We explore the gauge hierarchy problem within the framework of supersymmetric $SU(3)_c \times SU(3)_L \times SU(3)_R$ with a minimal set of higgs supermultiplets. Imposition of a suitable discrete (alternatively $R$) symmetry `prevents' the electroweak higgs doublets from becoming superheavy through renormalizable couplings. A full resolution of the problem requires consideration of the non-renormalizable couplings which play an essential role. Other key differences from the minimal supersymmetric $SU(5)$ model include the fact that the proton is stable and that an effective $5 + \bar{5}$ supermultiplet appears around the $TeV$ mass scale., Comment: LaTEX file, 16 pages, (Bartol Preprint BA-93-47)

We estimate the top quark, lightest sparticle (LSP) and scalar higgs masses within a supersymmetric grand unified framework in which $\tan\beta \simeq m_t/m_b$ and the electroweak symmetry is radiatively broken. The requirement that the calculated $b$ quark mass lie close to its measured value, together with the cosmological constraint $\Omega_{LSP} \approx 1$, fixes the top quark mass to be $m_t(m_t) \approx 170 \pm 15\ GeV$. The LSP (of bino purity $\stackrel{_>}{_\sim} 98\%)$ has mass $\sim 200 - 350\ GeV$. In the scalar higgs sector the CP-odd scalar mass $m_A \stackrel{_}{_\sim} M_Z$, as suggested by the decay $b \rightarrow s\gamma$, we find $M_Z \stackrel{_, Comment: 14 pages in plain LaTeX, BA-93-25, PRL-TH-93/6

We present an ansatz for the quark and lepton mass matrices, derivable from SO(10) type GUTs, which accommodates a heavy $(> 92 GeV)$ top quark and permits large mixings in the $\nu_\mu \leftrightarrow \nu_\tau$ sector (as suggested by the recent Kamiokande and IMB data on the atmospheric neutrinos). The well known asymptotic relations $m_b = m_\tau$, $m_s = \frac{1}{3} m_\mu$ and $m_dm_s = m_e m_\mu$ all hold to a good approximation. Depending on $\nu_\mu \leftrightarrow \nu_\tau$ mixing which can even be maximal, the mixing angle relevant for solar neutrino oscillation lies in the range $7.8 \times 10^{-3} \stackrel{_, Comment: 16 pages, in LaTeX

The simplest realizations of the new inflationary scenario typically give rise to primordial density fluctuations which deviate logarithmically from the scale free Harrison - Zeldovich spectrum. We consider a number of such examples and, in each case we normalize the amplitude of the fluctuations with the recent COBE measurement of the microwave background anisotropy. The predictions for the bulk velocities as well as anisotropies on smaller (~1-2 degrees) angular scales are compared with the Harrison-Zeldovich case. Deviations from the latter range from a few to about 15 percent. We also estimate the redshift beyond which the quasars would not be expected to be seen. The inflationary quasar cutoff redshifts can vary by as much as 25\% from the Harrison-Zeldovich case. We find that the inflationary scenario provides a good starting point for a theory of large scale structure in the universe provided the dark matter is a combination of cold plus (~10-30 \%) hot components., 20 pages,Latex file, BA-92-45,IC-92-118