scholarly journals Quasi-Classical Gravity Effect on Neutrino Oscillations in a Gravitational Field of a Heavy Astrophysical Object

2015 ◽  
Vol 2015 ◽  
pp. 1-15 ◽  
Author(s):  
Jonathan Miller ◽  
Roman Pasechnik
Keyword(s):  
Gravitational Field ◽  
Cross Sections ◽  
Large Angle ◽  
Classical Case ◽  
Indirect Detection ◽  
Quantum Decoherence ◽  
Gravity Effect ◽  
Weak Boson ◽  
Astrophysical Neutrinos ◽  
A New Technique

In the framework of quantum field theory, a graviton interacts locally with a quantum state having definite mass, that is, the gravitational mass eigenstate, while a weak boson interacts with a state having definite flavor, that is, the flavor eigenstate. An interaction of a neutrino with an energetic graviton may trigger the collapse of the neutrino to a definite mass eigenstate with probability expressed in terms of PMNS mixing matrix elements. Thus, gravitons would induce quantum decoherence of a coherent neutrino flavor state similarly to how weak bosons induce quantum decoherence of a neutrino in a definite mass state. We demonstrate that such an essentially quantum gravity effect may have strong consequences for neutrino oscillation phenomena in astrophysics due to relatively large scattering cross sections of relativistic neutrinos undergoing large angle radiation of energetic gravitons in gravitational field of a classical massive source (i.e., the quasi-classical case of gravitational Bethe-Heitler scattering). This graviton-induceddecoherenceis compared todecoherencedue to propagation in the presence of the Earth matter effect. Based on this study, we propose a new technique for the indirect detection of energetic gravitons by measuring the flavor composition of astrophysical neutrinos.

Shapes of optical emission lines from atoms excited by fast ion impact. II. Initial experimental results

1979 ◽  
Vol 57 (11) ◽  
pp. 1934-1939
Author(s):  
F. J. Morgan ◽  
C. H. Dugan ◽  
R. P. Lowe
Keyword(s):  
Spectral Line ◽  
Cross Sections ◽  
Line Shape ◽  
Large Angle ◽  
Optical Emission ◽  
New Technique ◽  
Experimental Conditions ◽  
Spectral Line Shape ◽  
Ion Impact ◽  
A New Technique

We present initial results of a new technique in which differential cross-section information is obtained by measuring the spectral line shape of emitted lines. We have measured the spectral line shape of the lithium resonance line at 670.7 nm (1s22s2S–1s22p2P) emitted following 5 keV Li+–He collision and compared it to the shape predicted on the basis of measured and theoretical cross sections using the method developed in paper I. Although broadening effects due to the particular experimental conditions used mask the details near the line centre, the shape of the wings of the line suggest that there is a significant amount of large angle scattering. The limitations of this new technique are discussed and it is concluded that, in the present case, cascade contribution to the population of the upper state is the most likely difficulty.

Gravity Effect on the Formation of Periodic Precipitation Patterns

2000 ◽  
Vol 65 (9) ◽  
pp. 1438-1442 ◽  
Author(s):  
Vladislav Holba ◽  
Frederik Fusek
Keyword(s):  
Gravitational Field ◽  
Spatial Arrangement ◽  
Experimental Results ◽  
Single Sample ◽  
Gravity Effect ◽  
Periodic Precipitation ◽  
Precipitation Patterns ◽  
Liesegang Bands

The effect of gravity on the formation of Liesegang patterns of Ag2Cr2O7in gelatin and that of PbI2in agar was investigated. Spatial arrangement of Liesegang bands was measured in the parallel and antiparallel orientation to the gravitational field in a single sample with all other parameters kept fixed. The experimental results are discussed in terms of the prenucleation theory of periodic precipitation.

scholarly journals Vector boson fusion at multi-TeV muon colliders

2020 ◽  
Vol 2020 (9) ◽  
Author(s):  
Antonio Costantini ◽  
Federico De Lillo ◽  
Fabio Maltoni ◽  
Luca Mantani ◽  
Olivier Mattelaer ◽  
...  
Keyword(s):  
Cross Sections ◽  
Vector Boson ◽  
High Energy ◽  
New Physics ◽  
Vector Boson Fusion ◽  
Weak Boson ◽  
Wide Range ◽  
Lepton Colliders ◽  
Muon Colliders ◽  
New Phenomena

Abstract High-energy lepton colliders with a centre-of-mass energy in the multi-TeV range are currently considered among the most challenging and far-reaching future accelerator projects. Studies performed so far have mostly focused on the reach for new phenomena in lepton-antilepton annihilation channels. In this work we observe that starting from collider energies of a few TeV, electroweak (EW) vector boson fusion/scattering (VBF) at lepton colliders becomes the dominant production mode for all Standard Model processes relevant to studying the EW sector. In many cases we find that this also holds for new physics. We quantify the size and the growth of VBF cross sections with collider energy for a number of SM and new physics processes. By considering luminosity scenarios achievable at a muon collider, we conclude that such a machine would effectively be a “high-luminosity weak boson collider,” and subsequently offer a wide range of opportunities to precisely measure EW and Higgs couplings as well as discover new particles.

scholarly journals Thermal Steady States of Gases in a Gravitational Field

2011 ◽  
Vol 66 (1-2) ◽  
pp. 123-133
Author(s):  
Kunihiko Kigoshi
Keyword(s):  
Heat Transfer ◽  
Gravitational Field ◽  
Temperature Difference ◽  
Thermal Gradient ◽  
Vertical Direction ◽  
Steady States ◽  
Gas Pressure ◽  
Experimental Results ◽  
Gravity Effect ◽  
Gas Molecules

This paper presents results on observations of a temperature difference between the top and bottom of a vessel filled with gas in a gravitational field. The observed temperature at the top of the vessel was always lower than the temperature at the bottom of the vessel, and this temperature difference was persistent and steady over more than 20 h. The magnitude of the temperature difference depends on the types of gas molecules present but is independent of the gas pressure in the vessel within the range from 2.7×104 Pa to 27 Pa. A temperature difference between the top and the bottom is only observed along the vertical direction and is only observed when the vessel contains a gas. These experimental results indicate a gravity effect on molecular heat transfer which enables the transport of energy in the gas without a thermal gradient.

scholarly journals Numerical and Experimental Study of Cross-Sectional Effects on the Mixing Performance of the Spiral Microfluidics

Micromachines ◽  
2021 ◽  
Vol 12 (12) ◽  
pp. 1470
Author(s):  
Omid Rouhi ◽  
Sajad Razavi Bazaz ◽  
Hamid Niazmand ◽  
Fateme Mirakhorli ◽  
Sima Mas-hafi ◽  
...  
Keyword(s):  
Cross Sections ◽  
Numerical Study ◽  
Large Angle ◽  
Element Model ◽  
Channel Length ◽  
Cross Sectional ◽  
Flow Rates ◽  
Lab On Chip ◽  
Mixing Performance ◽  
Dean Flow

Mixing at the microscale is of great importance for various applications ranging from biological and chemical synthesis to drug delivery. Among the numerous types of micromixers that have been developed, planar passive spiral micromixers have gained considerable interest due to their ease of fabrication and integration into complex miniaturized systems. However, less attention has been paid to non-planar spiral micromixers with various cross-sections and the effects of these cross-sections on the total performance of the micromixer. Here, mixing performance in a spiral micromixer with different channel cross-sections is evaluated experimentally and numerically in the Re range of 0.001 to 50. The accuracy of the 3D-finite element model was first verified at different flow rates by tracking the mixing index across the loops, which were directly proportional to the spiral radius and were hence also proportional to the Dean flow. It is shown that higher flow rates induce stronger vortices compared to lower flow rates; thus, fewer loops are required for efficient mixing. The numerical study revealed that a large-angle outward trapezoidal cross-section provides the highest mixing performance, reaching efficiencies of up to 95%. Moreover, the velocity/vorticity along the channel length was analyzed and discussed to evaluate channel mixing performance. A relatively low pressure drop (<130 kPa) makes these passive spiral micromixers ideal candidates for various lab-on-chip applications.

scholarly journals Two natural scenarios for dark matter particles coexisting with supersymmetry

2019 ◽  
Vol 34 (02) ◽  
pp. 1930001 ◽  
Author(s):  
Maxwell Throm ◽  
Reagan Thornberry ◽  
John Killough ◽  
Brian Sun ◽  
Gentill Abdulla ◽  
...  
Keyword(s):  
Dark Matter ◽  
Cross Sections ◽  
Higgs Sector ◽  
Weakly Interacting Massive Particles ◽  
Indirect Detection ◽  
Experimental Facilities ◽  
Direct And Indirect Detection ◽  
Extended Higgs Sector ◽  
Matter Component ◽  
Multicomponent Model

We describe two natural scenarios in which both dark matter, weakly interacting massive particles (WIMPs) and a variety of supersymmetric partners should be discovered in the foreseeable future. In the first scenario, the WIMPs are neutralinos, but they are only one component of the dark matter, which is dominantly composed of other relic particles such as axions. (This is the multicomponent model of Baer, Barger, Sengupta and Tata.) In the second scenario, the WIMPs result from an extended Higgs sector and may be the only dark matter component. In either scenario, both the dark matter WIMP and a plethora of other neutral and charged particles await discovery at many experimental facilities. The new particles in the second scenario have far weaker cross-sections for direct and indirect detection via their gauge interactions, which are either momentum-dependent or second-order. However, as we point out here, they should have much stronger interactions via the Higgs. We estimate that their interactions with fermions will then be comparable to (although not equal to) those of neutralinos with a corresponding Higgs interaction. It follows that these newly proposed dark matter particles should be within the reach of emerging and proposed facilities for direct, indirect and collider-based detection.

scholarly journals Experimental study of the wake behind a surface-piercing cylinder for a clean and contaminated free surface

2000 ◽  
Vol 402 ◽  
pp. 109-136 ◽  
Author(s):  
AMY WARNCKE LANG ◽  
MORTEZA GHARIB
Keyword(s):  
Surface Tension ◽  
Free Surface ◽  
Turbulent Flows ◽  
Cross Sections ◽  
Surface Deformation ◽  
Surface Condition ◽  
Free Surface Flows ◽  
Shear Stresses ◽  
Surface Contaminants ◽  
A New Technique

This experimental investigation into the nature of free-surface flows was to study the effects of surfactants on the wake of a surface-piercing cylinder. A better understanding of the process of vorticity generation and conversion at a free surface due to the absence or presence of surfactants has been gained. Surfactants, or surface contaminants, have the tendency to reduce the surface tension proportionally to the respective concentration at the free surface. Thus when surfactant concentration varies across a free surface, surface tension gradients occur and this results in shear stresses, thus altering the boundary condition at the free surface. A low Reynolds number wake behind a surface-piercing cylinder was chosen as the field of study, using digital particle image velocimetry (DPIV) to map the velocity and vorticity field for three orthogonal cross-sections of the flow. Reynolds numbers ranged from 350 to 460 and the Froude number was kept below 1.0. In addition, a new technique was used to simultaneously map the free surface deformation. Shadowgraph imaging of the free surface was also used to gain a better understanding of the flow. It was found that, depending on the surface condition, the connection of the shedding vortex filaments in the wake of the cylinder was greatly altered with the propensity for surface tension gradients to redirect the vorticity near the free surface to that of the surface-parallel component. This result has an impact on the understanding of turbulent flows in the vicinity of a free surface with varying surface conditions.

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