5,275 research outputs found
Vector Boson Pair Production in Hadronic Collisions at Order : Lepton Correlations and Anomalous Couplings
We present cross sections for production of electroweak vector boson pairs,
, and , in and collisions, at next-to-leading
order in . We treat the leptonic decays of the bosons in the
narrow-width approximation, but retain all spin information via decay angle
correlations. We also include the effects of and anomalous
couplings.Comment: 23 pages, 8 figures, 3 table
Strategy towards Mirror-fermion Signatures
The existence of mirror fermions interacting strongly under a new gauge group
and having masses near the electroweak scale has been recently proposed as a
viable alternative to the standard-model Higgs mechanism. The main purpose of
this work is to investigate which specific experimental signals are needed to
clearly differentiate the mirror-fermion model from other new-physics models.
In particular, the case is made for a future large lepton collider with c.o.m.
energies of roughly 4 TeV or higher.Comment: 30 Latex pages, 2 postscript figure
Cavity QED with separate photon storage and qubit readout modes
We present the realization of a cavity quantum electrodynamics setup in which
photons of strongly different lifetimes are engineered in different harmonic
modes of the same cavity. We achieve this in a superconducting transmission
line resonator with superconducting qubits coupled to the different modes. One
cavity mode is strongly coupled to a detection line for qubit state readout,
while a second long lifetime mode is used for photon storage and coherent
quantum operations. We demonstrate sideband based measurement of photon
coherence, generation of n photon Fock states and the scaling of the sideband
Rabi frequency with the square root of n using a scheme that may be extended to
realize sideband based two-qubit logic gates.Comment: 4 pages, 5 figures, version with high resolution figures available at
http://qudev.ethz.ch/content/science/PubsPapers.htm
On the Corrections to Dashen's Theorem
The electromagnetic corrections to the masses of the pseudoscalar mesons
and are considered. We calculate in chiral perturbation theory the
contributions which arise from resonances within a photon loop at order . Within this approach we find rather moderate deviations to Dashen's
theorem.Comment: 14 pages, sligthly enlarged version; a numerical error is corrected
and the embedding of the figures is improved. The complete paper, including
figures, is also available via anonymous ftp at
ftp://www-ttp.physik.uni-karlsruhe.de/ , or via www at
http://www-ttp.physik.uni-karlsruhe.de/cgi-bin/preprints/; to be published in
Phys.Rev.
Interference in Exclusive Vector Meson Production in Heavy Ion Collisions
Photons emitted from the electromagnetic fields of relativistic heavy ions
can fluctuate into quark anti-quark pairs and scatter from a target nucleus,
emerging as vector mesons. These coherent interactions are identifiable by
final states consisting of the two nuclei and a vector meson with a small
transverse momentum. The emitters and targets can switch roles, and the two
possibilities are indistinguishable, so interference may occur. Vector mesons
are negative parity so the amplitudes have opposite signs. When the meson
transverse wavelength is larger than the impact parameter, the interference is
large and destructive.
The short-lived vector mesons decay before amplitudes from the two sources
can overlap, and so cannot interfere directly. However, the decay products are
emitted in an entangled state, and the interference depends on observing the
complete final state. The non-local wave function is an example of the
Einstein-Podolsky-Rosen paradox.Comment: 13 pages with 3 figures; submitted to Physical Review Letter
Coherent Vector Meson Photoproduction with Nuclear Breakup in Relativistic Heavy Ion Collisions
Relativistic heavy ions are copious sources of virtual photons. The large
photon flux gives rise to a substantial photonuclear interaction probability at
impact parameters where no hadronic interactions can occur. Multiple
photonuclear interactions in a single collision are possible. In this letter,
we use mutual Coulomb excitation of both nuclei as a tag for moderate impact
parameter collisions. We calculate the cross section for coherent vector meson
production accompanied by mutual excitation, and show that the median impact
parameter is much smaller than for untagged production. The vector meson
rapidity and transverse momentum distribution are very different from untagged
exclusive vector meson production.Comment: 14 pages, including 4 figure
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