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.
119159662
Chern-Simons and WZW Anomaly Cancelations Across Dimensions
Abstract The WZW functional in D = 4 can be derived directly from the Chern–Simons functional of a compactified D = 5 gauge theory and the boundary fermions it supplants. A simple pedagogical model based on U ( 1 ) gauge groups illustrates how this works. A bulk-boundary system with the fermions eliminated manifestly evinces anomaly cancelations between CS and WZW terms.
969079
Anomaly mediated neutrino-photon interactions at finite baryon density.
We propose new physical processes based on the axial vector anomaly and described by the Wess-Zumino-Witten term that couples the photon, Z-boson, and the omega-meson. The interaction takes the form of a pseudo-Chern-Simons term, approximately E(munurhosigma)omega(mu)ZnuFrhosigma. This term induces neutrino-photon interactions at finite baryon density via the coupling of the Z-boson to neutrinos. These interactions may be detectable in various laboratory and astrophysical arenas. The new interactions may account for the excess observed at the Fermilab Booster Neutrino Experiment MiniBooNE. They also produce a competitive contribution to neutron star cooling at temperatures greater, similar10(9) K. These processes and related axion-photon interactions at finite baryon density appear to be relevant in many astrophysical regimes.
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.
54867630
Superconducting cosmic strings with massive fermions
Abstract Fermions which couple to the fields comprising a Nielsen-Olesen vortex (cosmic string) can generally exist as massive bound modes on the string. If these fermions carry electromagnetic charge then the string will interact with external electromagnetic fields in a manner significantly altered from the superconducting string scenario of Witten. The current in the string oscillates at a characteristic resonant frequency, ∼ ω , and therefore produces a signature of narrow band radiation. We also give an accounting of the relevant anomalies responsible for fermionic superconducting strings.
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.
118763369
GTS‐LHC: A New Source For The LHC Ion Injector Chain
The ion injector chain for the LHC has to be adapted and modified to reach the design beam parameters. Up to now an ECR4 delivered the ion beam for the SPS fixed target physics programme. This source will be replaced by a higher intensity source to produce the Pb27+ ion current required to fill the Low Energy Ion Ring (LEIR). The new ion source will be based on the Grenoble Test Source which was itself based on empirical scaling laws derived from the Framework 5 “Innovative ECRIS” collaboration. This paper will describe the design principle, the commissioning timetable and the present status of the source development.
107927154
Operation of the GTS-LHC Source for the Hadron Injector at CERN
The GTS-LHC ion source, designed and build by CEA Grenoble, was installed and commissioned at CERN in 2005. Since than the source has delivered oxygen and lead ion beams (O 4+ and Pb 27+ from the source, Pb 54+ from the linac) for the commissioning of the Low Energy Ion Ring (LEIR). Results of this operation and attempts to improve the source performance and reliability, and the linac performance will be presented in this paper.
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.
119530771
Acceleration in the linear non-scaling fixed-field alternating-gradient accelerator EMMA
In a fixed-field alternating-gradient (FFAG) accelerator, eliminating pulsed magnet operation permits rapid acceleration to synchrotron energies, but with a much higher beam-pulse repetition rate. Conceived in the 1950s, FFAGs are enjoying renewed interest, fuelled by the need to rapidly accelerate unstable muons for future high-energy physics colliders. Until now a ‘scaling’ principle has been applied to avoid beam blow-up and loss. Removing this restriction produces a new breed of FFAG, a non-scaling variant, allowing powerful advances in machine characteristics. We report on the first non-scaling FFAG, in which orbits are compacted to within 10 mm in radius over an electron momentum range of 12–18 MeV/c. In this strictly linear-gradient FFAG, unstable beam regions are crossed, but acceleration via a novel serpentine channel is so rapid that no significant beam disruption is observed. This result has significant implications for future particle accelerators, particularly muon and high-intensity proton accelerators.