Relativistic Heavy Ion Collider and the Large Hadron Collider for Heavy Ion Fusion

Heavy Ion Fusion makes use of the Relativistic Heavy Ion Collider at Brookhaven National Lab and the Large Hadron Collider in Geneva, Switzerland for Inertial Confinement Fusion. Two Storage Rings, which may or may not initially be needed, added to each of the Colliders increases the intensity of the Heavy Ion Beams making it comparable to the Total Energy delivered to the DT target by the National Ignition Facility at the Lawrence Livermore Lab. The basic Physics involved gives Heavy Ion Fusion an advantage over Laser Fusion because heavy ions have greater penetration power than photons. The Relativistic Heavy Ion Collider can be used as a Prototype Heavy Ion Fusion Reactor for the Large Hadron Collider.

Lambda polarization at the Electron-ion collider in China

Lambda polarization can be measured through its self-analyzing weak decay, making it an ideal candidate for studying spin effects in high-energy scattering. In lepton-nucleon deep inelastic scattering(DIS), Lambda polarization measurements can probe polarized parton distribution functions(PDFs) and polarized fragmentation functions(FFs). One of the most promising facilities for high-energy nuclear physics research is the proposed Electron-ion collider in China(EicC). As a next-generation facility, EicC is set to advance our understanding of nuclear physics to new heights. In this article, we study the Lambda production in electron-proton collisions at the EicC energy, in particular the reconstruction of Lambda based on the performance of the designed EicC detector. In addition, taking spontaneous transverse polarization as an example, we provide a theoretical prediction with a statistical projection based on one month of EicC data, offering valuable insights into future research prospects.

Beam-beam effects and mitigation in a future proton-proton collider

The beam-beam effects in a hadron collider with an unprecedented energy scale were studied.These effects are strongly related to the attainable luminosity of the collider.Long-range interactions were identified as the major factor limiting the dynamic aperture,which is strongly dependent on the crossing angle,β*,and bunch population.Different mitigation methods of the beam-beam effects were addressed,with a focus on the compensation of long-range interactions by electric curren wires.The CEPC-SPPC project is a two-stage large circular collider,with a first-stage circular electron-positron collider(CEPC)and a second-stage super proton-proton collider(SPPC).The design of the SPPC aims to achieve a center-of-mass energy of 75 TeV and peak luminosity of approximately 1×10^(35) cm^(-2)s^(-1).We studied the beam-beam effects in the SPPC and tested the effectiveness of the mitigation methods.We found that with compensation using electric current wires,the dynamic aperture is at an acceptable level.Moreover,considering the significant emittance damping in this future proton-proton collider the beam-beam effects and compensation are more complicated and are studied using long-term tracking.It was found that with a smaller emittance,the head-on interactions with a crossing angle become more prominent in reducing the beam stability,and combined head-on and long-range compensation is needed to improve the beam quality.When the reduction in population owing to burnoff was included,it was found that the coupling between the transverse and longitudinal planes at smaller emittance is the main driving source of the instabilities.Thus,crab cavities and emittance control are also necessary than just the compensation of the long-range interactions to improve the beam stability.This study serves as an example for studying the beam-beam effects in future proton-proton colliders.

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.

The B - L ＋ xY Model and the Higgs-strahlung Processes at a Collider

The gauge extension of the standard model with the U（1）B-L＋xy symmetry predicts the existence of a lightgauge boson Z′ with small couplings to ordinary fermions. We discuss its contributions to the muon anomalous magnetic moment αμ. Taking account of the constraints on the relevant free parameters, we further calculate the contributions of the light gauge boson Z′ to the Higgs-strahlung processes e＋ e-→ZH and e＋ e- →Z′H.

An SLC-Type e<sup>+</sup/>e<sup>&minus;</sup/>/γγ Facility at a Future Circular Collider

It is proposed to place the arcs of an SLC-type facility inside the tunnel of a Future Circular Collider (FCC). Accelerated by a linear accelerator (linac), electron and positron beams would traverse the bending arcs in opposite directions and collide at centre-of-mass energies considerably exceeding those attainable at circular e+e&minus;colliders. The proposed SLC-type facility would have the same luminosity as a conventional two-linace e+e&minus;collider. Using an optical free-electron laser, the facility could be converted into a γγ collider. A superconducting L-band linac at the proposed facility may form a part of the injector chain for a 100-TeV proton collider in the FCC tunnel. The whole accelerator complex would serve as a source of e+e&minus;, γγ, pp and ep interactions. The L-band linac could also be used to produce high-intensity neutrino, kaon and muon beams for fixed-target experiments, as well as X-ray free-electron laser (XFEL) photons for applications in material science and medicine.

Measuring Mass and Spin of Dark Matter Particles with the Aid Energy Spectra of Single Lepton and Dijet at the e⁺e^-Linear Collider

In many models stability of Dark Matter particles D is ensured by conservation of a new quantum number referred to as D -parity. Our models also contain charged D -odd particles D± with the same spin as D. (For more information,please refer to the PDF.)

An <i>e</i>⁺<i>e</i>^-/<i>γγ</i>/<i>ep</i>Accelerator Complex at a Future Circular Collider

This is the second paper by the author describing versatile accelerator complexes that could be built at a Future Circular Collider (FCC) in order to produce e+e-, γγ and ep collisions. The facility described here features an ILC-based e+e- collider placed tangentially to the FCC tunnel. If the collider is positioned asymmetrically with respect to the FCC tunnel, electron (or positron) bunches could be accelerated by both linacs before they are brought into collision with the 50-TeV beams from the FCC proton storage ring (FCC-pp). The two linacs may also form a part of the injector chain for FCC-pp. The facility could be converted into a γγ collider or a source of multi-MW beams for fixed-target experiments.

When Art & Finance Collide

Fine art and big finance are proving a profitable combination in China but questions of authenticity need to be addressed CHINA’S art market is on fire.As sales and prices break records,a new force has appeared in the market - organized art finance in the form of art trust funds and artwork exchanges.

Revisiting the top-quark pair production at future e^(+)e^(−)colliders

In this study,we reanalyze the top-quark pair production at next-to-next-to-leading order(NNLO)in quantum chromodynamics(QCD)at future e^(+)e^(−)colliders using the Principle of Maximum Conformality(PMC)method.The PMC renormalization scales inαs are determined by absorbing the non-conformalβterms by recursively using the Renormalization Group Equation(RGE).Unlike the conventional scale-setting method of fixing the scale at the center-of-mass energyμ_(r)=√s,the determined PMC scale Q_(⋆)is far smaller than the √sand increases with the √s,yielding the correct physical behavior for the top-quark pair production process.Moreover,the convergence of the pQCD series for the top-quark pair production is greatly improved owing to the elimination of the renormalon divergence.For a typical collision energy of √s=500 GeV,the PMC scale is Q_(⋆)=107 GeV;the QCD correction factor K for conventional results is K∼1+0.1244+0.0102+0.0012−0.0087−0.0011+0.0184−0.0086+0.0002+0.0061−0.0003,where the first error is caused by varying the scaleμr∈[√s/2,2√s]and the second error is from the top-quark massΔm_(t)=±0.7 GeV.After applying the PMC,the renormalization scale uncertainty is eliminated,and the QCD correction factor K is improved to K∼1+0.1507_(−0.0015)^(+0.0015)−0.0057_(−0.0000)^(+0.0001),where the error is from the top-quark massΔm_(t)=±0.7 GeV.The PMC improved predictions for the top-quark pair production are helpful for detailed studies of the properties of the top-quark at future e^(+)e^(−)colliders.

Phenomenology of heavy neutral gauge boson at muon collider

Heavy neutral gauge boson Z' is proposed in many new physics models.It has rich phenomena at the future muon collider.We study the properties of Z' boson with the process of μ^(+)μ^(-)→qq,μ^(+)μ^(-)→l^(+)l^(-),μ^(+)μ^(-)→ ZH and μ^(+)μ^(-)→ W^(+)W^(-).The discrepancy of Z' coupling to different types of particles can be shown in the cross section distributions around the resonance peak of various decay modes.Angular distributions of the final quark or lepton in μ^(+)μ^(-)→qq/l^(+)l^(-)process are sensitive to the parameters such as mass of Z' and the Z-Z' mixing angle.The interaction of new gauge boson coupling to the standard model gauge particles and Higgs boson are also studied through μ^(+)μ^(-)→ ZH→l^(+)l^(-)bb and μ^(+)u^(-)→ W^(+)W^(-)→l^(+)l^(-)v_(l)v_(l).The cross section and the final particles' angular distributions with the contribution of Z' boson differ from those processes with only standard model particles.A forward-backward asymmetry defined by the angular distribution is provided to show the potential of searching for new physics at the muon collider.Especially,the beam polarization with certain value can effectively enlarge the forward-backward asymmetry.

Leptonic di-flavor and di-number violation processes at high energyμ^(±)μ^(±)colliders

The leptonic di-flavor violation (LFV) processes μ^(±)μ^(±)→e^(±)e^(±) and μ^(±)μ^(±)→τ^(±)τ^(±) and leptonic di-number violation (LNV) processes μ^(±)μ^(±)→W_(i)^(±)W_(j)^(±) (i,j=1,2) at same-sign high energy μ^(±)μ^(±) colliders are studied. The new physics (NP) factors that may play roles in these processes are highlighted by cataloging them into three types. Taking into account the experimental constraints, the processes at μ^(±)μ^(±) colliders are computed, and the results are presented properly. The results lead to the conclusion that observing the NP factors through the LFV and LNV processes at TeV-energy μ^(±)μ^(±) colliders has significant advantages that cannot be achieved elsewhere. Therefore, once the techniques for muon acceleration and collision are developed successfully, the option of building same-sign high energy muon colliders should be seriously considered.

U(1)Lμ-Lτ breaking phase transition, muon g–2, dark matter, collider, and gravitational wave

Combining the dark matter and muon g-2 anomaly,we study the U(1)Lμ-Lτbreaking phase transition,gravitational wave spectra,and direct detection at the LHC in an extra U(1)Lμ-Lτgauge symmetry extension of the standard model.The new fields include vector-like leptons(E1,E2,N),the U(1)Lμ-Lτbreaking scalar S,and the gauge boson Z’,as well as the dark matter candidate XI and its heavy partner XR.A joint explanation of the dark matter relic density and muon g-2 anomaly excludes the region where both min(mE1,mE2,mN,mXR)and min(mZ’,mS)are much larger than mXI.In the parameter space accommodating the DM relic density and muon g-2 anomaly,the model can achieve a first-order U(1)Lμ-Lτbreaking phase transition,whose strength is sensitive to the parameters of the Higgs potential.The corresponding gravitational wave spectra can reach the sensitivity of UDECIGO.In addition,the direct searches at the LHC impose stringent bounds on the mass spectra of the vector-like leptons and dark matter.

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.

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.

Vector-like lepton searches at a muon collider in the context of the 4321 model

A feasibility study is performed on the search for vector-like leptons(VLLs)at a muon collider in the context of the"4321 model",an ultraviolet-complete model with rich collider phenomenology and the potential to explain several recent existing B physics measurements or anomalies.Pair production and decays of VLLs lead to an interesting final state topology with multi-jets and multi-tau leptons.In this study,we perform a Monte Carlo investigation with various machine learning techniques and examine the projected sensitivity on VLLs over a wide mass range at a TeV-scale muon collider.We find that a 3 TeV muon collider with only 10 fb^(−1) of data can be sensitive over the mass range of a VLL up to 1450 GeV in the"4321 model."

Search for the singlet vector-like top quark in the T→tZ channel with Z→vv at hadron colliders

Based on a simplified model including a singlet vector-like top quark T with charge|Q|=2/3,we analyze the prospects of observing T via the single T production in the tZ channel with Z decaying to neutrinos at the hadronhadron colliders.This simplified model only includes two free parameters,the coupling constant g^(*)and the T quark mass m_(T).To investigate the observability of the single T production,we perform a detailed background analysis and detector simulation for the collision energies 14 TeV,27 TeV,and 100 TeV.We scan the g^(*)-m_(T)parameter space and show the exclusion and discovery capabilities on the T quark with the highest integrated luminosity designed at these colliders.Moreover,the limits from the narrow-width approximation and electro weak precision observables are considered.

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.

Study of the gluonic quartic gauge couplings at muon colliders

The potential of muon colliders opens up new possibilities for the exploration of new physics beyond the Standard Model.It is worthwhile to investigate whether muon colliders are suitable for studying gluonic quartic gauge couplings(gQGCs),which can be contributed by dimension-8 operators in the framework of the Standard Model effective field theory,and are intensively studied recently.In this paper,we study the sensitivity of the processμ^(+)μ^(-)→jjν■to gQGCs.Our results indicate that the muon colliders with c.m.energies larger than 4 TeV can be more sensitive to gQGCs than the Large Hadron Collider.

Electron-ion collider in China

Lepton scattering is an established ideal tool for studying inner structure of small particles such as nucleons as well as nuclei.As a future high energy nuclear physics project,an Electron-ion collider in China(EicC)has been proposed.It will be constructed based on an upgraded heavy-ion accelerator,High Intensity heavy-ion Accelerator Facility(HIAF)which is currently under construction,together with a new electron ring.The proposed collider will provide highly polarized electrons(with a po-larization of 80%)and protons(with a polarization of 70%)with variable center of mass energies from 15 to 20 GeV and the luminosity of(2–3)×1033 cm^(−2)·s^(−1).Polarized deuterons and Helium-3,as well as unpolarized ion beams from Carbon to Uranium,will be also available at the EicC.The main foci of the EicC will be precision measurements of the structure of the nucleon in the sea quark region,including 3D tomography of nucleon;the partonic structure of nuclei and the parton interaction with the nuclear environment;the exotic states,especially those with heavy flavor quark contents.In addition,issues fundamental to understanding the origin of mass could be addressed by measurements of heavy quarkonia near-threshold production at the EicC.In order to achieve the above-mentioned physics goals,a hermetical detector system will be constructed with cutting-edge technologies.This document is the result of collective contributions and valuable inputs from experts across the globe.The EicC physics program complements the ongoing scientific programs at the Jefferson Laboratory and the future EIC project in the United States.The success of this project will also advance both nuclear and particle physics as well as accelerator and detector technology in China.