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The production of muons by collisions of primary cosmic ray particles with air nuclei is discussed. From these collisions pions and kaons are produced which then decay into muons. Two cases, oblique incidence and vertical incidence, are analyzed theoretically. Theoretical calculations agree well with observed data.
A turnable dye laser was used to measure the radiative lifetime of the individual rotational levels of the B2 Sigma (+) state of CN. The radiative lifetime of the unperturbed rotational levels is 65.6 plus or minus 1.0 nsec. A longer radiative lifetime of 72 plus or minus 1 nsec is observed for the Kaon prime = 4 level of the B state. The measured values of the perturbed and unperturbed levels support the longer lifetimes for the A2 meson pion state of CN. The quenching cross section of the B2 Sigma state of CN is 41 plus or minus 20 Angstroms squared and is independent of the rotational energy of the B state.
Secondary electron and positron fluxes generated in interstellar space and in the atmosphere from the decays of pions and kaons in inelastic nuclear interactions are calculated by Monte Carlo techniques for lepton energies in the range from 1 to 100 GeV and an assumed thickness of 10 g/sq cm or less for the interstellar or atmospheric material. A simple and accurate analytical model which summarizes the Monte Carlo results and identifies the essential parameters involved is developed and used to interpret a previous positron measurement. It is found that the thickness of interstellar and source material is about 4.3 g/sq cm for cosmic-ray positrons with energies exceeding 4 GeV, a result that is difficult to reconcile with recently proposed two-containment-volume propagation models which predict a thickness of 1.8 g/sq cm for the same energies on the basis of the energy dependence of the measured (Li+Be+B)/(C+O) ratio. It is shown that single-containment-volume (galactic) models invoking an energy-dependent leakage lifetime are compatible with the positron data, but lack a mechanism to explain the energy dependence.
An improved calculation of the secondary production and equilibrium spectrum of positrons and electrons in the Galaxy in the energy range from 1 MeV to 100 GeV has been performed. This has been done by obtaining an analytic representation of the accelerator data which describes accurately the invariant cross-section of pions, kaons, and their antiparticles from threshold energy to about 1500 GeV. This calculation takes into account the correct angular distribution of electrons in the decay of muons and the effect of nuclei-nuclei collisions. The contributions of beta-decay positrons and knock-on electrons have been included. A comparison of the present calculations with earlier calculations and experiment is presented.
Neutrino, gamma-ray, electron and positron production resulting from inelastic proton-proton collisions in a highly relativistic plasma such as may exist in extragalactic radio or gamma-ray burst sources is examined. The source functions of primary (pions, kaons, and neutrons) and secondary (photons, electrons, positrons and neutrinos) products of relativistic nuclear collisions are computed for the cases of power law and Maxwellian relativistic proton distributions. It is shown that in plasma which is optically thin to interactions between the plasma and secondary gamma-rays, electrons and positrons, only a small fraction of the initial energy is emitted in the observable form of neutrinos and gamma rays. In an optically thick plasma on the other hand, most of the energy of the relativistic protons is found to be equally divided between gamma rays and neutrinos, although only the neutrinos may escape freely to be observed.
When the high energy primary cosmic rays enter near the solar surface, they pass through a thick matter but having a low density. If the density and path length satisfy an appropriate condition, the primaries collide with the constituents near the solar sphere (almost protons) and produce pions and kaons, most of which decay into mu plus nu sub mu without successive hadron collisions. Muons also decay into NU sub mu and NU sub e before reaching the Earth. The neutrino flux of which the producer is matter near the solar surface is computed by solving cascade diffusion equations. The calculated differential flux of muon neutrino at 1 TeV is 1 X 10 to the minus 13 power (GeV. cm square centimeters 2.s.ster)(-1) which is rather difficult to be observed in the present apparatuses or DUMAND.
Nucleon decay detectors at large depths offers now a total area larger than 1000 sq m to registrate muons of energy exceeding 1 TeV. Near complete high energy muon families are detected in those arrays. An extensive 3D Monte-Carlo simulation was conducted in view to understand the spatial distribution of those events and the possible link with elementary act or primary composition. As pion or kaon parents have a very small decay probability at so high energy, multimuon phenomena occurs at high altitude where the atmospheric density is small after the most energetic collisions.
It is at present impossible to predict the interior constitution of neutron stars based on theory and results from laboratory studies. It has been proposed that it is possible to obtain information on neutron star interiors by studying thermal radiation from their surfaces, because neutrino emission rates, and hence the temperature of the central part of a neutron star, depend on the properties of dense matter. The theory predicts that neutron stars cool relatively slowly if their cores are made up of nucleons, and cool faster if the matter is in an exotic state, such as a pion condensate, a kaon condensate, or quark matter. This view has recently been questioned by the discovery of a number of other processes that could lead to copious neutrino emission and rapid cooling.
Accurate semiempirical parameterizations of the energy-differential cross sections for charged pion and kaon production from proton-proton collisions are presented at energies relevant to cosmic rays. The parameterizations, which depend on both the outgoing meson parallel momentum and the incident proton kinetic energy, are able to be reduced to very simple analytical formulas suitable for cosmic ray transport through spacecraft walls, interstellar space, the atmosphere, and meteorites.
A new class of tissue-equivalent proportional counters has been flown on two space shuttle flights. These detectors and their associated electronics cover a lineal energy range from 0.4 to 1250 keV/microns with a multichannel analyzer resolution of 0.1 keV/microns from 0.4 to 20 keV/microns and 5 keV/microns from 20 to 1250 keV/microns. These detectors provide the most complete dynamic range and highest resolution of any technique currently in use. On one mission, one detector was mounted in the Shuttle payload bay and another older model in the mid-deck, thus providing information on the depth dependence of the lineal energy spectrum. A detailed comparison of the observed lineal energy and calculated LET spectra for galactic cosmic radiation shows that, although the radiation transport models provide a rather accurate description of the dose (+/- 15%) and equivalent dose (+/- 15%), the calculations significantly underestimate the frequency of events below about 100 keV/microns. This difference cannot be explained by the inclusion of the contribution of splash protons. The contribution of the secondary pions, kaons and electrons produced in the Shuttle shielding, if included in the radiation transport model, may explain these differences. There are also significant differences between the model predictions and observations above 140 keV/microns, particularly for 28.5 degrees inclination orbit.
An electron can possess an electric dipole moment (edm) only if time reversal symmetry (T) is violated. No edm of any particle has yet been discovered. CP-violation, equivalent to T-violation by the CPT theorem, does occur in Kaon decays and can be accounted for by the standard model. However, this mechanism leads to an electron edm d(sub e) of the order of 10(exp -38) e cm, whereas the current experimental bound on d(sub e) is about 10(exp -27) e cm. However, well-motivated extensions of the standard model such as supersymmetric theories do predict that de could be as large as the current bound. In addition, CP violation in the early universe is required to explain the preponderance of matter over anti-matter, but the exact mechanism of this CP violation is unclear. For these reasons, we are undertaking a new experimental program to determine de to an improved accuracy of 10(exp -29) e cm. Our experiment will use laser-cooled, trapped Cesium atoms to measure the atomic edm d(sub Cs) that occurs if d(sub e) is not zero. In order to do this, we will measure the energy splitting between the atoms spin states in parallel electric and magnetic fields. The signature of an edm would be a linear dependence of the splitting on the electric field E due to the interaction - d(sub Cs) dot E. Our measurement will be much more sensitive than previous measurements because atoms can be stored in the trap for tens of seconds, allowing for much narrower Zeeman resonance linewidths. Also, our method eliminates the most important systematic errors, proportional to atomic velocity, which have limited previous experiments. In this presentation, we will describe the design of our new apparatus, which is presently under construction. An important feature of our experimental apparatus is that magnetic field noise will be suppressed to a very low value of the order of 1 fT/(Hz)1/2. This requires careful attention to the Johnson noise currents in the chamber, which have not been important in previous experiments. In addition we will present estimates of the limits of the various errors that we expect for our experiment.
Project X is a high intensity proton facility conceived to support a world-leading physics program at Fermilab. Project X will provide high intensity beams for neutrino, kaon, muon, and nuclei based experiments and for studies supporting energy applications. The Project X Injector Experiment (PIXIE) is a prototype of the Project X front end. A 30 MeV 50 kW beam will be used to validate the design concept of the Project X. This paper discusses a design of the accelerator enclosure radiation shielding and the beam dump.
We present a calculation of the $D\to K \ell \nu$ and $D\to\pi \ell \nu$ semileptonic form factors at $q^2=0$, which enable determinations of the CKM matrix elements $\lvert{V_{cs}}\rvert$ and $\lvert{V_{cd}}\rvert$, respectively. We use gauge-field configurations generated by the MILC collaboration with four flavors of highly-improved staggered (HISQ) quarks, analyzing several ensembles including those with physical pion masses and approximate lattice spacings ranging from 0.12~fm to 0.042~fm. We also use the HISQ action for the valence quarks. We employ twisted boundary conditions to calculate the form factors at zero momentum transfer directly. We use heavy-light-meson chiral perturbation theory modified for energetic pions and kaons, and supplemented by terms to describe the lattice-spacing dependence, to obtain preliminary results at the physical point and in the continuum limit.
We present results from Lattice QCD calculations of the low-lying charmed-strange meson spectrum using two types of Clover-Wilson lattices. In addition to quark-antiquark interpolating fields we also consider meson-meson interpolators corresponding to D-meson kaon scattering states. To calculate the all-to-all propagation necessary for the backtracking loops we use the (stochastic) distillation technique. For the charm quark we use the Fermilab method. Results for the $J^P=0^+$ $D_{s0}^*(2317)$ charmed-strange meson are presented.
Randall-Sundrum models are models of quark flavor, because they explain the hierarchies in the quark masses and mixings in terms of order one localization parameters of extra dimensional wavefunctions. The same small numbers which generate the light quark masses suppress contributions to flavor violating tree level amplitudes. In this note we update universal constraints from electroweak precision parameters and demonstrate how future measurements of flavor violation in ultra rare decay channels of Kaons and B mesons will constrain the parameter space of this type of models. We show how collider signatures are correlated with these flavor measurements and compute projected limits for direct searches at the 14 TeV LHC run, a 14 TeV LHC luminosity upgrade, a 33 TeV LHC energy upgrade, and a potential 100 TeV machine. We further discuss the effects of a warped model of leptons in future measurements of lepton flavor violation.
NOvA is a two-detector long-baseline neutrino oscillation experiment which aims to make a determination of the neutrino mass hierarchy, the octant of ${\theta}_{23}$, and measure possible CP violation. The NOvA Test Beam program consists of a scaled-down NOvA detector placed in a beamline capable of delivering 0.3 - 2.0 GeV/c protons, electrons, pions, and kaons. The beamline detectors provide us with particle identification and momentum measurements so we can study our detector technology with known inputs. Studying these particles will provide us a more detailed understanding of our calibration, detector response, and energy scale, which are some of the largest sources of systematic uncertainty in NOvA analyses. We will also collect a selection of single-particle data events for training particle identification algorithms. I will present the current status of the NOvA Test Beam program and discuss plans for data taking and analysis.
aHeavy Neutral Leptons (HNLs) offer a possible extension of the Standard Model via mixing with the three active neutrino flavours. HNLs with masses between 1 and 493 MeV can be produced from kaon and pion decays in the high-intensity Booster Neutrino Beam. These particles would then travel to the MicroBooNE detector where some fraction would decay in-flight to detectable Standard Model particles. This poster presents work to perform the first search for these particles in a liquid argon TPC. A number of methods are used to distinguish the HNL decays from the neutrino and cosmic ray background including utilising the time of flight of the massive HNL with respect to the active neutrinos. As the first search of its kind in a LArTPC this work pioneers techniques applicable for future large scale searches in the both the full Short Baseline Neutrino program and DUNE.
aThe motivation for the NOvA test beam project is to understand a number of limiting factors that impinges the NOvA's analyses. These factors include the detector’s hadronic and electromagnetic shower response, light yield and optical transportation, as well as discrepancies between data and MC modeling of the detector. In addition, the test beam setup will collect data to build a large libraries of particle interactions at well-known energies, which would later become a useful input in the development of better data driven PID algorithms for NOvA's analyses. The main component of the experiment - two 2$\times$2$\times$32 blocks, filled with NOvA liquid scintillator - is placed along the MC7 beamline to study the interaction with beam particles. The tertiary beam composes primarily of protons and pions as well as a discernible contribution from electrons, muons and kaons, all within a momentum range from 0.3 to 2 GeV$/c$. The PID and kinematics of beam particles will be determined by the auxiliary detectors including four MWPCs, two TOFs and a CO$_2$ gas Cherenkov counter. In this poster, recent status on beamline instrumentation, data acquisition, simulation, momentum reconstruction and PID will be presented. Also, implications for the neutrino oscillation measurements will be discussed.