5,646 research outputs found

### Using nu_e -> nu_tau: golden and silver channels at the Neutrino Factory

I briefly review the source of the so-called intrinsic ambiguity and show how
the combination of ``golden'' and ``silver'' channel at the Neutrino Factory
can solve the problem, in the absence of other sources of degeneracies. I then
relaxed the hypothesis $\theta_{23} = 45^\circ$ and show how the different
dependence of the two channels on $\theta_{23}$ can help in solving the
intrinsic and $\theta_{23}$-octant ambiguity at the same time.Comment: 6 pages, 7 figs. using epsfig; proceedings of the NOON 2003 Workshop,
February 10-14, 2003, Kanazawa, Japa

### $\nu_\mu$ disappearance at the SPL, T2K-I and the Neutrino Factory

We study the $\nu_\mu$ disappearance channel at T2K-phase I and the SPL and
analyse the achievable reduction of present uncertainties in $\theta_{23}$ and
$\Delta m^2_{23}$. We analyse the impact of discrete ambiguities in
sign($\Delta m^2{23}$) and sign($2 \tan \theta_{23}$). We show how the
disappearance channel at the Neutrino Factory is complementary to the
``golden'' and ``silver'' appearance channels and can be used to reduce the
eightfold-ambiguity problem in ($\theta_{13}-\delta$).Comment: 2 pages, 3 epsfig; NUFACT'05, 21-26 June 2005, Frascat

### Non-perturbative Renormalization of the Complete Basis of Four-fermion Operators and B-parameters

We present results on the B-parameters $B_K$, $B^{3/2}_7$ and $B^{3/2}_8$, at
$\beta=6.0$, with the tree-level Clover action. The renormalization of the
complete basis of dimension-six four-fermion operators has been performed
non-perturbatively. Our results for $B_K$ and $B^{3/2}_7$ are in reasonable
agreement with those obtained with the (unimproved) Wilson action. This is not
the case for $B^{3/2}_8$. We also discuss some subtleties arising from a
recently proposed modified definition of the B-parameters.Comment: Talk presented at Lattice '97, Edinburgh (UK), July 1997. LaTeX 3
pages, uses espcrc

### Physical Reach of a Neutrino Factory in the 2+2 and 3+1 Four-Family Scenario

We compare the physical reach of a Neutrino Factory in the 2+2 and 3+1
four-family models, with similar results in the two schemes; in both cases huge
CP-violating effects can be observed with a near detector in the $\nu_\mu \to
\nu_\tau$ channel. We also study the capability of long baseline experiments
(optimized for the study of the three-family mixing parameter space) in
distinguishing a three (active) neutrino model from a four-family scenario.Comment: 5 latex2e pages, 2 figures; talk given at NuFact '01, Tsukuba, 24-30
May 200

### The 2+2 and 3+1 Four-Family Neutrino Mixing at the Neutrino Factory

We upgrade the study of the physical reach of a Neutrino Factory in the Four
Family Neutrino Mixing scenario taking into account the latest LSND results
that points out how the 3+1 scheme cannot be completely ruled out within the
present experimental data (although the 2+2 scheme is still the preferred
choice when four neutrinos are considered). A detailed comparison of the
physical reach of the $\nu$-factory in the two schemes is given, with similar
results for the sensitivity to the mixing angles. Huge CP-violating effects can
be observed in both schemes with a near, O(10) Km, detector of O(10) Kton size
in the $\nu_\mu \to \nu_\tau$ channel. A smaller detector of 1 Kton size can
still observe very large effects in this channel.Comment: 38 Latex2e pages, 21 figures using epsfig, minor change

### Micro-orbits in a many-branes model and deviations from $1/r^2$ Newton's law

We consider a 5-dimensional model with geometry ${\cal M} = {\cal M}_4 \times
{\cal S}_1$, with compactification radius $R$. The Standard Model particles are
localized onto a brane located at y=0, with identical branes localized at
different points in the extra dimension. Objects located on our brane can orbit
around objects located on a brane at a distance $d=y/R$, with an orbit and a
period significantly different from the standard Newtonian ones. We study the
kinematical properties of the orbits, finding that it is possible to
distinguish one motion from the other in a large region of the initial
conditions parameter space. This is a warm-up to study if a SM-like mass
distribution on one (or more) distant brane(s) may represent a possible dark
matter candidate. After using the same technique to the study of orbits of
objects lying on the same brane ($d=0$), we apply this method to detect generic
deviations from the inverse-square Newton's law. We propose a possible
experimental setup to look for departures from Newtonian motion in the
micro-world, finding that an order of magnitude improvement on present bounds
can be attained at the 95% CL under reasonable assumptions.Comment: Two-column format (20 pages), 10 figures; minor corrections and some
added reference

### Quenched Supersymmetry

We study the effects of quenching in Super-Yang-Mills theory. While
supersymmetry is broken, the lagrangian acquires a new flavour $U(1 \mid 1)$
symmetry. The anomaly structure thus differs from the unquenched case. We
derive the corresponding low-energy effective lagrangian. As a consequence, we
predict the mass splitting expected in numerical simulations for particles
belonging to the lowest-lying supermultiplet.Comment: LATTICE98(yukawa), minor change

### Quenched Spectroscopy for the N=1 Super-Yang-Mills Theory

We present results for the Quenched SU(2) N=1 Super-Yang-Mills spectrum at
$\beta=2.6$, on a $V=16^3 \times 32$ lattice, in the OZI approximation. This is
a first step towards the understanding of the chiral limit of lattice N=1 SUSY.Comment: 3 pages, Latex, 2 ps figures, contribution to Lattice 97, Edinburgh
22-26 July 1997; to appear on Nucl. Phys. B. (Proc. Suppl.

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