4,587 research outputs found

### Prospects for single top cross section measurements at ATLAS with early data

We determine the sensitivity for single top cross section measurement for all three single top channels, using early ATLAS data (1-10 fb-1). Simple cut based analyses are presented along with more sophisticated tools (MVA). The results shown take into account our current knowledge of expected systematic uncertainties, theoretical cross sections, detector full simulation and trigger and reconstruction algorithm efficiencies

### Untangling CP Violation and the Mass Hierarchy in Long Baseline Experiments

In the overlap region, for the normal and inverted hierarchies, of the
neutrino-antineutrino bi-probability space for $\nu_\mu \to \nu_e$ appearance,
we derive a simple identity between the solutions in the ($\sin^2
2\theta_{13}$, $\sin \delta$) plane for the different hierarchies. The
parameter $\sin^2 2\theta_{13}$ sets the scale of the $\nu_\mu \to \nu_e$
appearance probabilities at the atmospheric $\delta m^2_{atm} \approx 2.4
\times 10^{-3}$ eV$^2$ whereas $\sin \delta$ controls the amount of CP
violation in the lepton sector. The identity between the solutions is that the
difference in the values of $\sin \delta$ for the two hierarchies equals twice
the value of $\sqrt{\sin^2 2\theta_{13}}$ divided by the {\it critical} value
of $\sqrt{\sin^2 2\theta_{13}}$. We apply this identity to the two proposed
long baseline experiments, T2K and NO$\nu$A, and we show how it can be used to
provide a simple understanding of when and why fake solutions are excluded when
two or more experiments are combined. The identity demonstrates the true
complimentarity of T2K and NO$\nu$A.Comment: 15 pages, Latex, 4 postscript figures. Submitted to New Journal of
Physics, ``Focus on Neutrino Physics'' issu

### Clone flow analysis for a theory inspired Neutrino Experiment planning

The presence of several clone solutions in the simultaneous measurement of
($\theta_{13},\delta$) has been widely discussed in literature. In this letter
we write the analytical formulae of the clones location in the
($\theta_{13},\delta$) plane as a function of the physical input pair
($\bar\theta_{13},\bar\delta$). We show how the clones move with changing
$\bar\theta_{13}$. The "clone flow" can be significantly different if computed
(naively) from the oscillation probabilities or (exactly) from the
probabilities integrated over the neutrino flux and cross-section.
Using our complete computation we compare the clone flow of a set of possible
future neutrino experiments: the CERN SuperBeam, BetaBeam and Neutrino Factory
proposals. We show that the combination of these specific BetaBeam and
SuperBeam does not help in solving the degeneracies. On the contrary, the
combination of one of them with the Neutrino Factory Golden and Silver channel
can be used, from a theoretical point of view, to solve completely the
eightfold degeneracy.Comment: 23 pages, using epsfi

### Complexity Results for Modal Dependence Logic

Modal dependence logic was introduced recently by V\"a\"an\"anen. It enhances
the basic modal language by an operator =(). For propositional variables
p_1,...,p_n, =(p_1,...,p_(n-1);p_n) intuitively states that the value of p_n is
determined by those of p_1,...,p_(n-1). Sevenster (J. Logic and Computation,
2009) showed that satisfiability for modal dependence logic is complete for
nondeterministic exponential time. In this paper we consider fragments of modal
dependence logic obtained by restricting the set of allowed propositional
connectives. We show that satisfibility for poor man's dependence logic, the
language consisting of formulas built from literals and dependence atoms using
conjunction, necessity and possibility (i.e., disallowing disjunction), remains
NEXPTIME-complete. If we only allow monotone formulas (without negation, but
with disjunction), the complexity drops to PSPACE-completeness. We also extend
V\"a\"an\"anen's language by allowing classical disjunction besides dependence
disjunction and show that the satisfiability problem remains NEXPTIME-complete.
If we then disallow both negation and dependence disjunction, satistiability is
complete for the second level of the polynomial hierarchy. In this way we
completely classify the computational complexity of the satisfiability problem
for all restrictions of propositional and dependence operators considered by
V\"a\"an\"anen and Sevenster.Comment: 22 pages, full version of CSL 2010 pape

### Summary of Golden Measurements at a $\nu$-Factory

The precision and discovery potential of a neutrino factory based on muon
storage rings is summarized. For three-family neutrino oscillations, we analyze
how to measure or severely constraint the angle $\theta_{13}$, CP violation,
MSW effects and the sign of the atmospheric mass difference $\Delta m^2_{23}$.
The appearance of ``wrong-sign muons'' at three reference baselines is
considered: 732 km, 3500 km and 7332 km. We exploit the dependence of the
signal on the neutrino energy, and include as well realistic background
estimations and detection efficiencies. The optimal baseline turns out to be
$O$(3000 km).Comment: 7 pages, Latex2e, 5 eps figures, use package espfi

### Golden measurements at a neutrino factory

The precision and discovery potential of a neutrino factory based on muon
storage rings is studied. For three-family neutrino oscillations, we analyse
how to measure or severely constraint the angle $\theta_{13}$, CP violation,
MSW effects and the sign of the atmospheric mass difference $\Delta m^2_{23}$.
We present a simple analytical formula for the oscillation probabilities in
matter, with all neutrino mass differences non-vanishing, which clarifies the
subtleties involved in disentangling the unknown parameters. The appearance of
``wrong-sign muons'' at three reference baselines is considered: 732 km, 3500
km, and 7332 km. We exploit the dependence of the signal on the neutrino
energy, and include as well realistic background estimations and detection
efficiencies. The optimal baseline turns out to be ${\cal O}(3000$ km).
Analyses combining the information from different baselines are also presented.Comment: 45 pages, Latex2e, 24 figures using epsfig.sty. An incorrect
statement and a few misprints have been corrected. Results and conclusions
are unchange

### Unveiling Neutrino Mixing and Leptonic CP Violation

We review the present understanding of neutrino masses and mixings,
discussing what are the unknowns in the three family oscillation scenario.
Despite the anticipated success coming from the planned long baseline neutrino
experiments in unraveling the leptonic mixing sector, there are two important
unknowns which may remain obscure: the mixing angle $\theta_{13}$ and the
CP-phase $\delta$. The measurement of these two parameters has led us to
consider the combination of superbeams and neutrino factories as the key to
unveil the neutrino oscillation picture.Comment: Invited brief review, 18 pages, 6 figure

### CP, T and CPT violation in future long baseline experiments

I give a short overview about the possibilities and problems related to the
measurement of CP violation in long baseline experiments. Special attention is
paid to the issue of degeneracies and a method for their resolution is
quantitatively discussed. The CP violation reach for different experiments is
compared in dependence of $\sin^22\theta_{13}$ and \dm{21}. Furthermore a
short comment about the possible effects of matter induced T violation is made.
Finally the limits on CPT violation obtainable at a neutrino factory are shown.Comment: Talk presented at NUFACT02, London, 1-6 July, 2002. 3 pages, 2
figure

### Precision on leptonic mixing parameters at future neutrino oscillation experiments

We perform a comparison of the different future neutrino oscillation
experiments based on the achievable precision in the determination of the
fundamental parameters theta_{13} and the CP phase, delta, assuming that
theta_{13} is in the range indicated by the recent Daya Bay measurement. We
study the non-trivial dependence of the error on delta on its true value. When
matter effects are small, the largest error is found at the points where CP
violation is maximal, and the smallest at the CP conserving points. The
situation is different when matter effects are sizable. As a result of this
effect, the comparison of the physics reach of different experiments on the
basis of the CP discovery potential, as usually done, can be misleading. We
have compared various proposed super-beam, beta-beam and neutrino factory
setups on the basis of the relative precision of theta_{13} and the error on
delta. Neutrino factories, both high-energy or low-energy, outperform
alternative beam technologies. An ultimate precision on theta_{13} below 3% and
an error on delta of < 7^{\circ} at 1 sigma (1 d.o.f.) can be obtained at a
neutrino factory.Comment: Minor changes, matches version accepted in JHEP. 30 pages, 9 figure

### Resolving Octant Degeneracy at LBL experiment by combining Daya Bay Reactor Setup

Long baseline Experiment (LBL) have promised to be a very powerful
experimental set up to study various issues related to Neutrinos. Some ongoing
and planned LBL and medium baseline experiments are - T2K, MINOS, NOvA, LBNE,
LBNO etc. But the long baseline experiments are crippled due to presence of
some parameter degeneracies, like the Octant degeneracy. In this work, we first
show the presence of Octant degeneracy in LBL experiments, and then combine it
with Daya Bay Reactor experiment, at different values of CP violation phase. We
show that the Octant degeneracy in LBNE can be resolved completely with this
proposal.Comment: 4 pages, 8 figure

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