16412795
Deconstructing 5D QED
We discuss periodic compactification and latticization of a 5D $U(1)$ theory with a Dirac fermion, yielding a $1+3$ effective theory. We address subtleties in the lattice fermionic action, such as fermion doubling and the Wilson term. We compute the Coleman-Weinberg potential for the Wilson line which is finite for N-branes $g~3,$ due to the ${Z}_{N}$ symmetry, which replaces translations in the $5\mathrm{th}$ dimension. This mode becomes a PNGB in the low energy $1+3$ theory. We derive its anomalous coupling to the ``photon'' and its KK modes.
119473346
Renormalization group fixed points and the Higgs boson spectrum
Abstract We study numerically the renormalization group equations for the Higgs potential of the two-doublet model assuming perturbative unification and sufficiently large initial quartic and Higgs-Yukawa couplings such that the full nonlinearities interplay. We obtain predictions for the physical Higgs boson spectrum in the two-doublet model up to systematic differences in fermion coupling schemes. Unambiguous predictions emerge only when there exists a heavy generation in which quarks couple to both doublets. In other cases we find that the potential can become quartically unstable at low energies for arbitrary initial stable values of the coupling constants.
10472717
Chiral multiplets of heavy-light mesons
The recent discovery of a narrow resonance in ${D}_{s}{\ensuremath{\pi}}^{0}$ by the BaBar Collaboration is consistent with the interpretation of a heavy ${J}^{P}{(0}^{+}{,1}^{+})$ spin multiplet. This system is the parity partner of the ground state ${(0}^{\ensuremath{-}}{,1}^{\ensuremath{-}})$ multiplet, which we argue is required in the implementation of ${\mathrm{SU}(3)}_{L}\ifmmode\times\else\texttimes\fi{}{\mathrm{SU}(3)}_{R}$ chiral symmetry in heavy-light meson systems. The ${(0}^{+}{,1}^{+})\ensuremath{\rightarrow}{(0}^{\ensuremath{-}}{,1}^{\ensuremath{-}})+\ensuremath{\pi}$ transition couplings satisfy a Goldberger-Treiman relation, ${g}_{\ensuremath{\pi}}=\ensuremath{\Delta}{M/f}_{\ensuremath{\pi}},$ where $\ensuremath{\Delta}M$ is the mass gap. The BaBar resonance fits the ${0}^{+}$ state, with a kinematically blocked principal decay mode to $D+K.$ The allowed ${D}_{s}+\ensuremath{\pi},$ ${D}_{s}+2\ensuremath{\pi},$ and electromagnetic transitions are computed from the full chiral theory and found to be suppressed, consistent with the narrowness of the state. This state establishes the chiral mass difference for all such heavy-quark chiral multiplets, and precise predictions exist for the analogous ${B}_{s}$ and strange doubly heavy baryon states.
122717656
Renormalization in indefinite metric theories
We consider the Lee model,V ⇆ N+θ, and a two neutral scalar meson model with indefinite metrics. It is shown that in general the coupling will cause positive definite bare states to become negative length dressed states through renormalization effects. This can render the theory unphysical depending upon the auxiliary conditions imposed with the indefinite metric.
15028896
Fractal theory space: Space-time of noninteger dimensionality
We construct matter field theories in ``theory space'' that are fractal, and invariant under geometrical renormalization group (RG) transformations. We treat in detail complex scalars, and discuss issues related to fermions, chirality, and Yang-Mills gauge fields. In the continuum limit these models describe physics in a noninteger spatial dimension which appears above a RG invariant ``compactification scale,'' M. The energy distribution of KK modes above M is controlled by an exponent in a scaling relation of the vacuum energy (Coleman-Weinberg potential), and corresponds to the dimensionality. For truncated-s-simplex lattices with coordination number s the spacetime dimensionality is 1+(3+2ln(s)/ln(s+2)). The computations in theory space involve subtleties, owing to the 1+3 kinetic terms, yet the resulting dimensionalites are equivalent to thermal spin systems. Physical implications are discussed.
11755173
Cosmology with ultralight pseudo Nambu-Goldstone bosons.
We explore the cosmological implications of an ultralight pseudo Nambu-Goldstone boson. With global spontaneous symmetry breaking scale $f\ensuremath{\simeq}{10}^{18}\mathrm{GeV}$ and explicit breaking scale comparable to Mikheyev-Smirnov-Wolfenstein neutrino masses, $M\ensuremath{\sim}{10}^{\ensuremath{-}3}\mathrm{eV}$, such a field, which acquires a mass ${m}_{\ensuremath{\varphi}}\ensuremath{\sim}{M}^{2}/f\ensuremath{\sim}{H}_{0}$, would currently dominate the energy density of the Universe. The field acts as an effective cosmological constant before relaxing into a condensate of nonrelativistic bosons. Such a model can reconcile dynamical estimates of the density parameter, ${\ensuremath{\Omega}}_{m}\ensuremath{\sim}0.2$, with a spatially flat universe, yielding ${H}_{0}{t}_{0}\ensuremath{\simeq}1$ consistent with limits from gravitational lens statistics.
117846161
Utilizing the ECR afterglow to increase the intensity of highly charged ions in the CERN accelerator complex
121802815
The LEAR Electron Cooler: Recent Improvements and Tests
Recent work on the electron cooling device at the CERN Low Energy Antiproton Ring (LEAR) is summarized. This included an improvement of the collector performance and of the vacuum. Relations between the different cooler parameters were measured with a view to simplifying the control system. Results of vacuum tests performed before the installation in LEAR are presented, and a short description of the status of the cooling device after its installation is given.
29994289
Acceleration and stacking of α particles in the CERN Linac, PS and ISR
The CERN Intersecting Storage Rings (ISR) have been successfully operated with sufficient α particles for experiments at total center of mass energies up to 120 GeV. Initially, the small beam currents obtainable from the (old) Linac hampered machine studies with the PS so that conclusive experiments similar to those done with deuterons were not possible. Recent attempts to increase the intensity by stripping a He+ beam at 520 keV succeeded and gave 10 mA of α particles from the Linac. Multiturn injection and acceleration in the PS produced 2×10<sup>11</sup> particles/pulse and stacking in the ISR resulted in a maximum stored beam intensity of 4.2 A at 52 GeV. After further acceleration by phase displacement in the ISR, luminosities of 4×10<sup>28</sup>cm<sup>-2</sup>s<sup>-1</sup> for α-α and 9×10<sup>29</sup>cm<sup>-2</sup>s<sup>-1</sup> for α-p experiments were obtained.
73538214
Recent lead ion storage tests on LEAR
With the completion of the antiproton physics program, the Low Energy Antiproton Ring is now available to be used as an accumulator ring for heavy ions in the LBC injector chain. The proposed scheme for the injection of Pb ions is given, where an intensity gain of 125 is obtained by accumulating Pb ions with electron cooling in the LEAR ring. With a linac cycling at 10 Hz and cooling times faster than 100 ms, 20 pulses can be accumulated in 2 s before transfer to the PS, the next machine in the chain. A number of machine experiments have been performed and will continue this year, in order to establish the techniques required. We discuss injection line tests, ion beam lifetime and vacuum measurements and cooling time measurements.
118292647
New beam for the CERN fixed target heavy ion programme