Wireless Network Requirements and Solutions for the Future Circular Collider:A Hostile Indoor Environment

The European organization for nuclear research(CERN)is planning a high performance particle collider by 2050,which will update the currently used Large Hadron Collider(LHC).The design of the new experiment facility includes the definition of a suitable communication infrastructure to support the future needs of scientists.The huge amount of data collected by the measurement devices call for a data rate of at least 1 Gb/s per node,while the need of timely control of instruments requires a low latency of the order of 0.01μs.Moreover,the main tunnel will be 100 km long,and will need appropriate coverage for voice and data traffic,in a special underground environment subject also to strong radiations.Reliable voice,data and video transmission in a tunnel of this length is necessary to ensure timely and localized intervention,reducing access time.In addition,using wireless communication for voice,control and data acquisition of accelerator technical systems could lead to a significant reduction in cabling costs,installation times and maintenance efforts.The communication infrastructure of the Future Circular Collider(FCC)tunnel must be able to circumvent the problems of radioactivity,omnipresent in the tunnel.Current technologies transceivers cannot transmit in such a severely radioactive environment.This is due to the immediate destruction of any active or passive equipment by radioactivity.The scope of this paper is to determine the feasibility of robust wireless transmission in an underground radioactive tunnel environment.The network infrastructure design to meet the demand will be introduced,and the performance of different wireless technologies will be evaluated.

Two-photon physics at future electron-positron colliders

Two photon collisions offer a variety of physics phenomena that can be studied at future electronpositron colliders.Using the planned CEPC parameters as a benchmark,we consider several topics within twophoton collisions.With the full integrated luminosity,Higgs boson photoproduction can be reliably observed,and large statistics on various quarkonium states can be collected.The LEP results for the photon structure function and tau lepton anomalous magnetic moment can be improved by 1-2 orders of magnitude.

Search for heavy Majorana neutrinos at future lepton colliders

A nonzero neutrino mass may be a sign of new physics beyond the standard model(SM).To explain the small neutrino mass,we can extend the SM using right-handed Majorana neutrinos in a low-scale seesaw mechanism,and the CP violation effect can be induced due to the CP phase in the interference of heavy Majorana neutrinos.The existence of heavy Majorana neutrinos may lead to lepton number violation processes,which can be used to search for the signals of heavy Majorana neutrinos.In this paper,we focus on the CP violation effect related to two generations of heavy Majorana neutrinos at 15 GeV<m_(N1)<70 GeV in the pair production of W bosons and rare decays.It is valuable to investigate Majorana neutrino production signals and the related CP violation effects in rare W boson decays at future lepton colliders.

Exploring muonphilic ALPs at muon colliders

Axion-like particles(ALPs)are new particles that extend beyond the standard model(SM)and are extensively investigated.When considering ALPs within an effective field theory framework,their couplings with SM particles can be studied independently.It is a daunting task to search for GeV-scale ALPs coupled to muons in collider experiments because their coupling is proportional to the muon mass.However,a recent study by Altmannshofer,Dror,and Gori(2022)highlighted the importance of a four-point interaction,W-μ-νμ-a,as well as interactions from the chiral anomaly,whose couplings are not dependent on the muon mass.These interactions provide a new opportunity to explore muonphilic ALPs(μALPs)at the GeV scale.We explore variousμALP production channels at muon colliders withμALPs decaying into a pair of muons.In particular,we find that a pair of neutrinos accompanied by aμALP is the most effective channel to search forμALPs in the electrowek violating(EWV)scenario.In contrast,a photon plus aμALP becomes a better channel to search forμALPs in the electroweak preserving(EWP)scenario because there is no W-μ-νμ-a interaction in this situation.Most importantly,we find that the future bounds forμALPs in the EWV scenario are considerably stronger than those in the EWP scenario and the existing bounds for exploringμALPs with 1 GeV≤ma≲MW.

Importance of heavy quark longitudinal structure function measurements at future circular collider energies

In this article,we consider the ratio of structure functions for heavy quark pair production at low values of.The importance of this ratio for charm and beauty pair production is examined according to the Hadron Electron Ring Accelerator(HERA)data.The behavior of these ratios is considered due to the hard pomeron behavior of the gluon distribution function.The results are in good agreement with the HERA data.Expanding this data to the range of new energies underscores the importance of these measurements for heavy quarks.The ratio of charm and beauty structure functions at the proposed Large Hadron electron Collider(LHeC)is considered as a function of invariant center-of-mass energy.For top pair production this ratio is extracted with known kinematics of the LHeC and Future Circular Collider electron-hadron(FCC-eh)colliders.Comparison of the results obtained for the ratio of top structure functions in LHeC and FCC-eh are proportional to the specified inelasticity range.

One-loop contributions for h→ℓℓγ and e−e+→hγ in the U(1)_(B−L) extension of the standard model

We present one-loop contributions for h→ℓℓγ with ℓ=νe,μ,τ,e,μ and e−e+→hγ in the U(1)_(B−L) extension of the standard model. In the phenomenological results, the signal strengths for h→ℓℓγ at the Large Hadron Collider and for e−e+→hγ at future lepton colliders are analyzed in the physical parameter space for both the vector and chiral B−L models. We found that the contributions from the neutral gauge boson Z′ to the signal strengths are rather small. Consequently, the effects will be difficult to probe at future colliders. However, the impacts of charged Higgs and CP-odd Higgs in the chiral B−L model on the signal strengths are significant and can be measured with the help of the initial polarization beams at future lepton colliders.

MSSM at future Higgs factories

In this work,we study the implications of Higgs precision measurements at future Higgs factories for the MSSM parameter space,focusing on the dominant stop sector contributions.We perform a multivariable fit to both the signal strength for various Higgs decay channels at Higgs factories and the Higgs mass.The χ^(2)fit results show sensitivity to m_(A),tan β,stop mass parameter m_(SUSY),and the stop left-right mixing parameter Xt.We also study the impact of the Higgs mass prediction on the MSSM and compare the sensitivities of different Higgs factories.

One-loopformulas for H→Zν_(ι)ν_(ι),forιe,μ,τin't Hooft-Veltman gauge

In this paper,we present analytical results for one-loop contributions to the decay processes H-Zvivi(for I=e,μ,T).The calculations are performed within the Standard Model framework in the't Hooft-Veltman gauge.One-loop form factors are then written in terms of scalar one-loop functions in the standard notations of LoopTools.As a result,one-loop decay rates for the decay channels can be evaluated numerically by using the package.Furthermore,we analyze the signals of H→Zvivi via the production processes e-e+→ZH*-Z(H*→Zν_(ι)ν_(ι)),including the initial beam polarizations at future lepton colliders.The Standard Model backgrounds,such as the processes e-e+→ν_(ι)ν_(ι)ZZ,are also examined in this study.Numerical results indicate that one-loop corrections make contributions of approximately 10%to the decay rates.These are sizeable contributions and should be taken into account at future colliders.We show that the signals H-Zν_(ι)ν_(ι)are clearly visible at the center-of-mass energy√s=250 GeV and are difficult to probe in higher-energy regions owing to the dominant backgrounds.

ArborTracking:a tree topology track pattern recognition algorithm

Purpose The purpose of this work is to develop a novel pattern tracking algorithm to be used on the detectors of the future electron-positron colliders.Method ArborTracking,a light-weighted tracking algorithm,has been developed based on the tree topology of track clusters and applied to the baseline detector of the circular electron-positron collider(CEPC).The algorithm collects all the hits in the tracker as a tree(forest),splits the tree branches to form the track segments,and merges the track segments to form the tracks.Results Compared with the general track following method,the algorithm has the advantages of low coding complicity and low CPU cost.The performances at different benchmarks are studied.The results are exhaustively listed showing that the method is approaching the limit of the detector.The tracking efficiencies on single muon sample and three-prong sample are both higher than 99%.The transverse momentum resolution reaches 0.1%level and the boson mass resolution reaches 4.7 GeV/c.Conclusions The performances are similar with those of the baseline tracking algorithm of CEPC,and the physics requirement of CEPC is satisfied.The new tree pattern recognition algorithm is a necessary part in the CEPC software.And it is also a competitive algorithm on the market,which can be chosen by the future experiments.