scholarly journals THE CASE OF αs: Z VERSUS LOW ENERGIES OR, HOW NATURE SHOWS US NEW PHYSICS

1996 ◽  
Vol 11 (18) ◽  
pp. 3195-3225 ◽  
Author(s):  
M. SHIFMAN
Keyword(s):  
High Energy ◽  
New Physics ◽  
Current Status ◽  
Low Energies

The values of αs determined from low and high energy measurements are in irreconcilable contradiction with each other. The current status of the problem is critically reviewed. Consequences of the αs contradiction, in conjunction with other anomalies detected at the Z peak, are discussed. This article has been updated in accordance with experimental numbers reported at summer conferences.

scholarly journals Prospects of direct search for dark photon and dark Higgs in SeaQuest/E1067 experiment at the Fermilab main injector

2017 ◽  
Vol 32 (10) ◽  
pp. 1730008 ◽  
Author(s):  
Ming Xiong Liu
Keyword(s):  
Mass Range ◽  
High Energy ◽  
New Physics ◽  
Mass Region ◽  
Electromagnetic Calorimeter ◽  
Current Status ◽  
Dark Sector ◽  
Dark Photon ◽  
Near Future ◽  
Search Program

In this review, we present the current status and prospects of the dark sector physics search program of the SeaQuest/E1067 fixed target dimuon experiment at Fermilab Main Injector. There has been tremendous excitement and progress in searching for new physics in the dark sector in recent years. Dark sector refers to a collection of currently unknown particles that do not directly couple with the Standard Model (SM) strong and electroweak (EW) interactions but assumed to carry gravitational force, thus could be candidates of the missing Dark Matter (DM). Such particles may interact with the SM particles through “portal” interactions. Two of the simple possibilities are being investigated in our initial search: (1) dark photon and (2) dark Higgs. They could be within immediate reach of current or near future experimental search. We show there is a unique opportunity today at Fermilab to directly search for these particles in a highly motivated but uncharted parameter space in high-energy proton–nucleus collisions in the beam-dump mode using the 120 GeV proton beam from the Main Injector. Our current search window covers the mass range 0.2–10 GeV/c2, and in the near future, by adding an electromagnetic calorimeter (EMCal) to the spectrometer, we can further explore the lower mass region down to about [Formula: see text][Formula: see text]1 MeV/c2 through the di-electron channel. If dark photons (and/or dark Higgs) were observed, they would revolutionize our understanding of the fundamental structures and interactions of our universe.

PRECISION LOW ENERGY WEAK NEUTRAL CURRENT EXPERIMENTS

1995 ◽  
Vol 10 (39) ◽  
pp. 2979-2992 ◽  
Author(s):  
K.S. KUMAR ◽  
E.W. HUGHES ◽  
R. HOLMES ◽  
P.A. SOUDER
Keyword(s):  
High Energy Physics ◽  
Neutral Current ◽  
High Energy ◽  
New Physics ◽  
Coupling Constants ◽  
Current Status ◽  
Weak Neutral Current ◽  
Weak Mixing Angle ◽  
Precision Data ◽  
Moller Scattering

Precision measurements of weak neutral current amplitudes at [Formula: see text] are a sensitive probe of contact interactions arising from new high energy physics. Such measurements significantly enhance the analysis of precision data on the Z0 resonance, permitting tests of the running of the electroweak coupling constants. The behavior of the coupling constants as a function of Q2 can reveal the presence of many possible new physics scenarios, such as new gauge bosons, superparticles and substructure; some of these effects are difficult to observe on the Z0 pole. In order to probe energy scales up to 1 TeV, future low Q2 measurements must be precise enough to measure electroweak radiative corrections. Two experimental programs which aim to reach this sensitivity are deep inelastic neutrino nucleon scattering and atomic parity violation experiments. Another important technique is polarized electron scattering off unpolarized targets. We review the current status and future prospects of such measurements. We present an experimental design to measure the left-right parity violating asymmetry in polarized Møller scattering (e−e−→e−e−), which could constitute the most precise measurement of the weak mixing angle [Formula: see text] at [Formula: see text].

scholarly journals Ion tracks in silicon formed by much lower energy deposition than the track formation threshold

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
H. Amekura ◽  
M. Toulemonde ◽  
K. Narumi ◽  
R. Li ◽  
A. Chiba ◽  
...  
Keyword(s):  
Nuclear Energy ◽  
Energy Deposition ◽  
Ion Irradiation ◽  
High Energy ◽  
Electronic Energy ◽  
Synergy Effect ◽  
Ion Tracks ◽  
Track Formation ◽  
Low Energies ◽  
High Energy Ions

AbstractDamaged regions of cylindrical shapes called ion tracks, typically in nano-meters wide and tens micro-meters long, are formed along the ion trajectories in many insulators, when high energy ions in the electronic stopping regime are injected. In most cases, the ion tracks were assumed as consequences of dense electronic energy deposition from the high energy ions, except some cases where the synergy effect with the nuclear energy deposition plays an important role. In crystalline Si (c-Si), no tracks have been observed with any monomer ions up to GeV. Tracks are formed in c-Si under 40 MeV fullerene (C60) cluster ion irradiation, which provides much higher energy deposition than monomer ions. The track diameter decreases with decreasing the ion energy until they disappear at an extrapolated value of ~ 17 MeV. However, here we report the track formation of 10 nm in diameter under C60 ion irradiation of 6 MeV, i.e., much lower than the extrapolated threshold. The diameters of 10 nm were comparable to those under 40 MeV C60 irradiation. Furthermore, the tracks formed by 6 MeV C60 irradiation consisted of damaged crystalline, while those formed by 40 MeV C60 irradiation were amorphous. The track formation was observed down to 1 MeV and probably lower with decreasing the track diameters. The track lengths were much shorter than those expected from the drop of Se below the threshold. These track formations at such low energies cannot be explained by the conventional purely electronic energy deposition mechanism, indicating another origin, e.g., the synergy effect between the electronic and nuclear energy depositions, or dual transitions of transient melting and boiling.

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 The low-energy effective theory of axions and ALPs

2021 ◽  
Vol 2021 (4) ◽  
Author(s):  
Martin Bauer ◽  
Matthias Neubert ◽  
Sophie Renner ◽  
Marvin Schnubel ◽  
Andrea Thamm
Keyword(s):  
High Energy ◽  
New Physics ◽  
Mass Scale ◽  
Low Energy ◽  
Effective Theory ◽  
Loop Order ◽  
Flavor Changing ◽  
Effective Lagrangian ◽  
Anomalous Dimensions ◽  
Pseudoscalar Mesons

Abstract Axions and axion-like particles (ALPs) are well-motivated low-energy relics of high-energy extensions of the Standard Model, which interact with the known particles through higher-dimensional operators suppressed by the mass scale Λ of the new-physics sector. Starting from the most general dimension-5 interactions, we discuss in detail the evolution of the ALP couplings from the new-physics scale to energies at and below the scale of electroweak symmetry breaking. We derive the relevant anomalous dimensions at two-loop order in gauge couplings and one-loop order in Yukawa interactions, carefully considering the treatment of a redundant operator involving an ALP coupling to the Higgs current. We account for one-loop (and partially two-loop) matching contributions at the weak scale, including in particular flavor-changing effects. The relations between different equivalent forms of the effective Lagrangian are discussed in detail. We also construct the effective chiral Lagrangian for an ALP interacting with photons and light pseudoscalar mesons, pointing out important differences with the corresponding Lagrangian for the QCD axion.

scholarly journals A Compact Review of Laser Welding Technologies for Amorphous Alloys

Metals ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1690
Author(s):  
Jian Qiao ◽  
Peng Yu ◽  
Yanxiong Wu ◽  
Taixi Chen ◽  
Yixin Du ◽  
...  
Keyword(s):  
Amorphous Alloy ◽  
Laser Welding ◽  
Amorphous Alloys ◽  
High Energy ◽  
Industrial Applications ◽  
High Energy Density ◽  
Current Status ◽  
Future Research ◽  
Technological Parameters ◽  
Fast Heating

Amorphous alloys have emerged as important materials for precision machinery, energy conversion, information processing, and aerospace components. This is due to their unique structure and excellent properties, including superior strength, high elasticity, and excellent corrosion resistance, which have attracted the attention of many researchers. However, the size of the amorphous alloy components remains limited, which affects industrial applications. Significant developments in connection with this technology are urgently needed. Laser welding represents an efficient welding method that uses a laser beam with high energy-density for heating. Laser welding has gradually become a research hotspot as a joining method for amorphous alloys due to its fast heating and cooling rates. In this compact review, the current status of research into amorphous-alloy laser welding technology is discussed, the influence of technological parameters and other welding conditions on welding quality is analyzed, and an outlook on future research and development is provided. This paper can serve as a useful reference for both fundamental research and engineering applications in this field.

scholarly journals Characterizing new physics with polarized beams at high-energy hadron colliders

2014 ◽  
Vol 2014 (5) ◽  
Author(s):  
Benjamin Fuks ◽  
Josselin Proudom ◽  
Juan Rojo ◽  
Ingo Schienbein
Keyword(s):  
High Energy ◽  
New Physics ◽  
Hadron Colliders ◽  
Polarized Beams ◽  
Energy Hadron

scholarly journals New vistas in charm production

2019 ◽  
Vol 206 ◽  
pp. 02004
Author(s):  
Antoni Szczurek
Keyword(s):  
Large Deviations ◽  
Transition Probabilities ◽  
High Energy ◽  
Lhcb Collaboration ◽  
Charm Production ◽  
High Energy Neutrino ◽  
Neutrino Production ◽  
Energy Neutrino ◽  
Low Energies

We discuss some new aspects of charm production trigerred by recent observations of the LHCb collaboration. The LHCb collaboration measured small asymmetries in production of D+D−mesons as well as $ D_s^ + D_s^ - $ mesons. Is this related to initial quark/antiquark asymmetries in the proton ? Here we discuss a scenario in which unfavored fragmentations $ q/\bar {q} \to D $ and $ s/\bar {s} \to D_s $ are responsible for the asymmetries. We fix the strength of such fragmentations – transition probabilities, by adjusting to the size of the LHCb asymmetries. This has consequences for production of D mesons in forward directions (large xF ) as well as at low energies. Large asymmetries are predicted then in these regions. We present here some of our predictions. Consequences for high-energy neutrino production in the atmosphere are discussed and quantified. The production of Λc baryon at the LHC is disussed. Large deviations from the independent-parton fragmentation picture are found.

scholarly journals Exploring $$\hbox {CE}\nu \hbox {NS}$$ with NUCLEUS at the Chooz nuclear power plant

2019 ◽  
Vol 79 (12) ◽  
Author(s):  
G. Angloher ◽  
F. Ardellier-Desages ◽  
A. Bento ◽  
L. Canonica ◽  
A. Erhart ◽  
...  
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Nuclear Power ◽  
Sensitivity Study ◽  
New Physics ◽  
Low Energy ◽  
Cryogenic Detectors ◽  
Reduction Techniques ◽  
Low Energies ◽  
Nuclear Recoils

AbstractCoherent elastic neutrino–nucleus scattering ($$\hbox {CE}\nu \hbox {NS}$$CEνNS) offers a unique way to study neutrino properties and to search for new physics beyond the Standard Model. Nuclear reactors are promising sources to explore this process at low energies since they deliver large fluxes of anti-neutrinos with typical energies of a few MeV. In this paper, a new-generation experiment to study $$\hbox {CE}\nu \hbox {NS}$$CEνNS is described. The NUCLEUS experiment will use cryogenic detectors which feature an unprecedentedly low-energy threshold and a time response fast enough to be operated under above-ground conditions. Both sensitivity to low-energy nuclear recoils and a high event rate tolerance are stringent requirements to measuring $$\hbox {CE}\nu \hbox {NS}$$CEνNS of reactor anti-neutrinos. A new experimental site, the Very-Near-Site (VNS), at the Chooz nuclear power plant in France is described. The VNS is located between the two 4.25 $$\hbox {GW}_{\mathrm {th}}$$GWth reactor cores and matches the requirements of NUCLEUS. First results of on-site measurements of neutron and muon backgrounds, the expected dominant background contributions, are given. In this paper a preliminary experimental set-up with dedicated active and passive background reduction techniques and first background estimations are presented. Furthermore, the feasibility to operate the detectors in coincidence with an active muon veto at shallow overburden is studied. The paper concludes with a sensitivity study pointing out the physics potential of NUCLEUS at the Chooz nuclear power plant.

scholarly journals W-boson production in the high energy electron-photon collisions

2019 ◽  
pp. 41-50
Author(s):  
Ivan A. Shershan ◽  
Tatiana V. Shishkina
Keyword(s):  
Standard Model ◽  
Cross Sections ◽  
W Boson ◽  
High Energy ◽  
New Physics ◽  
Coupling Constants ◽  
Boson Production ◽  
The Standard Model ◽  
Electron Photon ◽  
W Boson Production

In this paper the analysis of W-boson production process in high-energy electron-photon collisions as a tool to search for deviations from the Standard Model is considered. In particular, a set of extended gauge models, including anomalous multi-boson interactions, are discussed as a promising way for «new physics» study. A numerical analysis of the total cross sections of the processes was carried out. The lowest order radiative corrections in the soft-photon approximation within the Standard Model are taken into account. Calculations beyond the Standard Model was performed, the kinematic features of the cross sections were identified. The restrictions on the anomalous triple gauge boson coupling constants were analyzed and the kinematic areas to the search for their manifestations were obtained during the experiments at the International Linear Collider. The paper shows that the search for «new physics» effects based on electron-photon collisions around the W-boson production peak is the maximal promising. It was also shown that future experiments at high luminosity linear colliders will significantly clarify the constraints on anomalous gauge coupling constants.

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