Higgs physics at future lepton colliders

2018 ◽  
Vol 33 (31) ◽  
pp. 1844003
Author(s):  
Mario Greco
Keyword(s):  
Higgs Physics ◽  
Higgs Particle ◽  
Radiative Effects ◽  
Decay Channels ◽  
Electron Positron ◽  
Lepton Colliders ◽  
Muon Collider ◽  
Resonant Production ◽  
Muon Colliders

Various proposals of electron and muon colliders have been put forward for precision studies of the Higgs properties. It is shown that in both cases of Higgs resonant production through a muon collider, and associated HZ production in a electron–positron collider sizeable QED radiative effects must be carefully taken into account for the precise measurements of the decay channels of the Higgs particle.

scholarly journals On the study of the Higgs properties at a muon collider

2015 ◽  
Vol 30 (39) ◽  
pp. 1530031 ◽  
Author(s):  
Mario Greco
Keyword(s):  
Standard Model ◽  
Precise Measurement ◽  
Higgs Production ◽  
Detailed Knowledge ◽  
Higgs Particle ◽  
Decay Channels ◽  
Electron Positron ◽  
The Standard Model ◽  
Muon Collider ◽  
Muon Colliders

The discovery of the Higgs particle at 125 GeV is demanding a detailed knowledge of the properties of this fundamental component of the Standard Model. To that aim various proposals of electron and muon colliders have been put forward for precision studies of the partial widths of the various decay channels. It is shown that in the case of a Higgs factory through a muon collider, sizeable radiative effects — of order of 50% — must be carefully taken into account for a precise measurement of the leptonic and total widths of the Higgs particle. Similar effects do not apply in the case of Higgs production in electron–positron colliders.

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 Hunting wino and higgsino dark matter at the muon collider with disappearing tracks

2021 ◽  
Vol 2021 (6) ◽  
Author(s):  
Rodolfo Capdevilla ◽  
Federico Meloni ◽  
Rosa Simoniello ◽  
Jose Zurita
Keyword(s):  
Dark Matter ◽  
Simple Strategy ◽  
Physics Program ◽  
Daunting Task ◽  
Muon Collider ◽  
New States ◽  
Muon Colliders ◽  
Particle Decays ◽  
Electrically Charged

Abstract We study the capabilities of a muon collider experiment to detect disappearing tracks originating when a heavy and electrically charged long-lived particle decays via X+→ Y+Z0, where X+ and Z0 are two almost mass degenerate new states and Y+ is a charged Standard Model particle. The backgrounds induced by the in-flight decays of the muon beams (BIB) can create detector hit combinations that mimic long-lived particle signatures, making the search a daunting task. We design a simple strategy to tame the BIB, based on a detector-hit-level selection exploiting timing information and hit-to-hit correlations, followed by simple requirements on the quality of reconstructed tracks. Our strategy allows us to reduce the number of tracks from BIB to an average of 0.08 per event, hence being able to design a cut-and-count analysis that shows that it is possible to cover weak doublets and triplets with masses close to $$ \sqrt{s}/2 $$ s / 2 in the 0.1–10 ns range. In particular, this implies that a 10 TeV muon collider is able to probe thermal MSSM higgsinos and thermal MSSM winos, thus rivaling the FCC-hh in that respect, and further enlarging the physics program of the muon collider into the territory of WIMP dark matter and long-lived signatures. We also provide parton-to-reconstructed level efficiency maps, allowing an estimation of the coverage of disappearing tracks at muon colliders for arbitrary models.

scholarly journals Resonant Production of an Ultrarelativistic Electron–Positron Pair at the Gamma Quantum Scattering by a Field of the X-ray Pulsar

Universe ◽  
2020 ◽  
Vol 6 (10) ◽  
pp. 164
Author(s):  
Vadim A. Yelatontsev ◽  
Sergei P. Roshchupkin ◽  
Viktor V. Dubov
Keyword(s):  
Gamma Quantum ◽  
Threshold Energy ◽  
Structure Constant ◽  
Fine Structure Constant ◽  
Quantum Scattering ◽  
X Ray ◽  
Ultrarelativistic Electron ◽  
Electron Positron ◽  
Resonant Production ◽  
Electron Positron Pair

The process of a resonant production of an ultrarelativistic electron–positron pair in the process of gamma-quantum scattering in the X-ray field of a pulsar is theoretically studied. This process has two reaction channels. Under resonant conditions, an intermediate electron (for a channel A) or a positron (for a channel B) enters the mass shell. As a result, the initial second-order process of the fine-structure constant in the X-ray field effectively splits into two first-order processes: the X-ray field-stimulated Breit–Wheeler process and the the X-ray field-stimulated Compton effect on an intermediate electron or a positron. The resonant kinematics of the process is studied in detail. It is shown that for the initial gamma quantum there is a threshold energy, which for the X-ray photon energy (1–102) keV has the order of magnitude (103–10) MeV. In this case, all the final particles (electron, positron, and final gamma quantum) fly in a narrow cone along the direction of the initial gamma quantum momentum. It is important to note that the energies of the electron–positron pair and the final gamma quantum depend significantly on their outgoing angles. The obtained resonant probability significantly exceeds the non-resonant one. The obtained results can be used to explain the spectrum of positrons near pulsars.

Resonant production of electron-positron pairs by a hard gamma-ray on a nucleus in an external electromagnetic field

2020 ◽  
Vol 35 (03) ◽  
pp. 2040025 ◽  
Author(s):  
Nikita R. Larin ◽  
Victor V. Dubov ◽  
Sergei P. Roshchupkin
Keyword(s):  
Electromagnetic Field ◽  
Differential Cross Section ◽  
External Field ◽  
Cross Section ◽  
Differential Cross ◽  
Gamma Ray ◽  
Structure Constant ◽  
External Electromagnetic Field ◽  
Electron Positron ◽  
Resonant Production

The resonant production of electron-positron pairs by a hard gamma-ray on nucleus in an external electromagnetic field is studied theoretically. The main property of this process is that the initial process of the second order in the fine structure constant in an external field effectively splits into two successive processes of the first order due to the fact that in resonant conditions intermediate virtual electron (positron) becomes a real particle. One of these processes is a single-photoproduction of electron-positron pair in a laser field (laser-stimulated Breit-Wheeler process) another is a laser-assisted scattering of electron (positron) on nucleus (laser-assisted Mott scattering). It is shown that the resonances are possible only for the energies of the initial hard gamma-ray more than the characteristic threshold energy. Resonant differential cross section of this process is obtained. It is shown that the resonant differential cross section can significantly exceed the corresponding cross section without an external field. The obtained results may be experimentally verified using the facilities of pulsed laser radiation (SLAC, FAIR, XFEL, ELI, XCELS).

scholarly journals PRODUCTION OF (τ+τ-) IN ELECTRON–POSITRON COLLISIONS

2009 ◽  
Vol 24 (20n21) ◽  
pp. 4039-4044
Author(s):  
A. A. MALIK ◽  
I. S. SATSUNKEVICH
Keyword(s):  
Cross Section ◽  
Atomic System ◽  
Energy Levels ◽  
Radiative Corrections ◽  
Experimental Conditions ◽  
Decay Channels ◽  
Electron Positron ◽  
Decay Widths ◽  
Positron Collisions

(τ+τ-) is an atom of simple hydrogenlike structure similar to positronium (e-e+) and (μ+μ-). In this paper energy levels and decay widths of different decay channels of (τ+τ-) are given. Cross-section of production of this atomic system in e-e+ annihilation taking into account radiative corrections is calculated. According to our estimates 31 (τ+τ-) atoms are produced at VEPP-4M and 943 (τ+τ-) atoms may be produced at BEPCII under the present experimental conditions.

scholarly journals Higgs physics possibilities at a Muon Collider

2021 ◽  
Author(s):  
Lorenzo Sestini ◽  
Paolo Andreetto ◽  
Camilla Curatolo ◽  
Alessio Gianelle ◽  
Donatella Lucchesi ◽  
...  
Keyword(s):  
Higgs Physics ◽  
Muon Collider

scholarly journals Particle identification for Higgs physics at future electron–positron collider

2020 ◽  
Vol 35 (15n16) ◽  
pp. 2041013 ◽  
Author(s):  
Wei-Ming Yao
Keyword(s):  
Higgs Physics ◽  
Yukawa Coupling ◽  
High Energy Physics ◽  
Flavor Physics ◽  
High Energy ◽  
Particle Identification ◽  
Heavy Flavor ◽  
Electron Positron ◽  
Physics Experiments ◽  
Energy Physics

Particle identification (PID) plays a key role in heavy-flavor physics in high-energy physics experiments. However, its impact on Higgs physics is still not clear. In this note, we will explore some of the potential of PID to improve the identification of heavy-flavor jets by using identified charged kaons in addition to the traditional vertexing information. This could result in a better measurement of the Higgs-charm Yukawa coupling at the future [Formula: see text] colliders.

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