Search results for "Observable"
showing 10 items of 634 documents
Discerning the Origins of the Amplitude Fluctuations in Dynamic Raman Nanospectroscopy
2012
International audience; We introduce a novel experimental and analytical method for discerning rare surface-enhanced Raman scattering (SERS) events observable at the nanoscale. We show that the kinetics of the Raman activity recorded on an isolated nanostructure is punctuated by intense and rare events of large amplitude and spectral variations. The fluctuations of thousands of SERS spectra were analyzed statistically in terms of power density functions, and the occurrence of the rare events was quantified by a wavenumber statistics. Our analysis enables one to extract valuable and unique spectroscopic signature of Raman variations usually hidden in time-average or space-average measurement…
Chiral theory of nucleons and pions in the presence of an external gravitational field
2020
We extend the standard second order effective chiral Lagrangian of pions and nucleons by considering the coupling to an external gravitational field. As an application we calculate one-loop corrections to the one-nucleon matrix element of the energy-momentum tensor to fourth order in chiral counting, and next-to-leading order tree-level amplitude of the pion-production in an external gravitational field. We discuss the relation of the obtained results to experimentally measurable observables. Our expressions for the chiral corrections to the nucleon gravitational form factors differ from those in the literature. That might require to revisit the chiral extrapolation of the lattice data on t…
Structure of transactinide nuclei with relativistic energy density functionals
2013
A microscopic theoretical framework based on relativistic energy density functionals (REDFs) is applied to studies of shape evolution, excitation spectra, and decay properties of transactinide nuclei. Axially symmetric and triaxial relativistic Hartree-Bogoliubov (RHB) calculations, based on the functional DD-PC1 and with a separable pairing interaction, are performed for the even-even isotopic chains between Fm and Fl. The occurrence of a deformed shell gap at neutron number $N=162$ and its role on the stability of nuclei in the region around $Z=108$ is investigated. A quadrupole collective Hamiltonian, with parameters determined by self-consistent constrained triaxial RHB calculations, is…
Weak kaon production off the nucleon and Watson's theorem
2021
We have improved the tree-level model of Ref arXiv:1004.5484 [hep-ph] for weak production of kaons off nucleons by partially restoring unitarity. This is achieved by imposing Watson's theorem to the dominant vector and axial-vector contributions in appropriate angular momentum and isospin quantum number sectors. The observable consequences of this procedure are investigated.
Phenomenology of maximal and near-maximal lepton mixing
2000
We study the phenomenological consequences of maximal and near-maximal mixing of the electron neutrino with other ($x$=tau and/or muon) neutrinos. We describe the deviations from maximal mixing in terms of a parameter $\epsilon\equiv1-2\sin^2\theta_{ex}$ and quantify the present experimental status for $|\epsilon|<0.3$. We find that the global analysis of solar neutrino data allows maximal mixing with confidence level better than 99% for $10^{-8}$ eV$^2\lsim\Delta m^2\lsim2\times10^{-7}$ eV$^2$. In the mass ranges $\Delta m^2\gsim 1.5\times10^{-5}$ eV$^2$ and $4\times10^{-10}$ eV$^2\lsim\Delta m^2\lsim2\times10^{-7}$ eV$^2$ the full interval $|\epsilon|<0.3$ is allowed within 4$\sigma$(99.9…
Neutrinos, DUNE and the world best bound on CPT invariance
2017
CPT symmetry, the combination of Charge Conjugation, Parity and Time reversal, is a cornerstone of our model building strategy and therefore the repercussions of its potential violation will severely threaten the most extended tool we currently use to describe physics, i.e. local relativistic quantum fields. However, limits on its conservation from the Kaon system look indeed imposing. In this work we will show that neutrino oscillation experiments can improve this limit by several orders of magnitude and therefore are an ideal tool to explore the foundations of our approach to Nature. Strictly speaking testing CPT violation would require an explicit model for how CPT is broken and its effe…
Neutrino Mass from Cosmology
2012
Neutrinos can play an important role in the evolution of the Universe, modifying some of the cosmological observables. In this contribution we summarize the main aspects of cosmological relic neutrinos and we describe how the precision of present cosmological data can be used to learn about neutrino properties, in particular their mass, providing complementary information to beta decay and neutrinoless double-beta decay experiments. We show how the analysis of current cosmological observations, such as the anisotropies of the cosmic microwave background or the distribution of large-scale structure, provides an upper bound on the sum of neutrino masses of order 1 eV or less, with very good p…
Power Corrections to Event Shapes with Mass-Dependent Operators
2013
We introduce an operator depending on the "transverse velocity'' r that describes the effect of hadron masses on the leading 1/Q power correction to event-shape observables. Here, Q is the scale of the hard collision. This work builds on earlier studies of mass effects by Salam and Wicke [J. High Energy Phys. 05 (2001) 061] and of operators by Lee and Sterman [Phys. Rev. D 75, 014022 (2007)]. Despite the fact that different event shapes have different hadron mass dependence, we provide a simple method to identify universality classes of event shapes whose power corrections depend on a common nonperturbative parameter. We also develop an operator basis to show that at a fixed value of Q, the…
Evaluating the double parton scattering contribution to Mueller-Navelet jets production at the LHC
2015
We propose a model to study the importance of double parton scattering (DPS) in Mueller-Navelet jets production at the LHC which is consistent with the BFKL framework used to compute the single parton scattering contribution to this process. We study this model in kinematics corresponding to existing and possible future measurements at the LHC and estimate the importance of this DPS contribution on relevant observables for this process, namely the cross section and the azimuthal correlation of the jets.
A model of neutrino mass and dark matter with large neutrinoless double beta decay
2017
We propose a model where neutrino masses are generated at three loop order but neutrinoless double beta decay occurs at one loop. Thus we can have large neutrinoless double beta decay observable in the future experiments even when the neutrino masses are very small. The model receives strong constraints from the neutrino data and lepton flavor violating decays, which substantially reduces the number of free parameters. Our model also opens up the possibility of having several new scalars below the TeV regime, which can be explored at the collider experiments. Additionally, our model also has an unbroken $Z_2$ symmetry which allows us to identify a viable Dark Matter candidate.