Hasil untuk "physics.acc-ph"

Zetao Xie, Zeling Chen, Hao Li et al.

The emerging field of free-electron quantum optics enables electron-photon entanglement and holds the potential for generating nontrivial photon states for quantum information processing. Although recent experimental studies have entered the quantum regime, rapid theoretical developments predict that qualitatively unique phenomena only emerge beyond a certain interaction strength. It is thus pertinent to identify the maximal electron-photon interaction strength and the materials, geometries, and particle energies that enable one to approach it. We derive an upper limit to the quantum vacuum interaction strength between free electrons and single-mode photons, which illuminates the conditions for the strongest interaction. Crucially, we obtain an explicit energy selection recipe for electrons and photons to achieve maximal interaction at arbitrary separations and identify two optimal regimes favoring either fast or slow electrons over those with intermediate velocities. We validate the limit by analytical and numerical calculations on canonical geometries and provide near-optimal designs indicating the feasibility of strong quantum interactions. Our findings offer fundamental intuition for maximizing the quantum interaction between free electrons and photons and provide practical design rules for future experiments on electron-photon and electron-mediated photon-photon entanglement. They should also enable the evaluation of key metrics for applications such as the maximum power of free-electron radiation sources and the maximum acceleration gradient of dielectric laser accelerators.

K. I. Beloborodov, T. A. Kharlamova, V. I. Telnov

The process of elastic scattering of photons (scattering of light by light) has attracted much attention in recent years. It goes through a loop where all the charged particles contribute to the cross section. To date, this $γγ\to γγ$ process has been experimentally studied in the Delbrück scattering and splitting of photons in the Coulomb field of the nucleus, as well as at the LHC in the scattering of virtual photons in ion-ion collisions. Hopes for further study of this process are associated with high-luminosity $e^+e^-$ colliders (SuperKEKb, FCC, CEPC, ILC, CLIC) and gamma-gamma colliders based on the Compton scattering of laser photons on electrons. In this article, we show that there are some very serious background processes where the annihilation of electrons and positrons (real and virtual) produces a pair of photons flying into the detector, and the the remaining products fly away from the detector at small angles.

Dawei Fu, Alim Ruzi, Meng Lu et al.

We propose methods to produce energetic meson beams such as charged and neutral Kaons, which are boosted to be collimated and with relatively long life time. The first type of methods is based on asymmetric electron positron collisions with a center of mass energy of, e.g., 1020 MeV, and Kaons can be produced at a rate of $10^{4-5}/s$. The electron and positron beams are either asymmetric in energy, e.g., 10 GeV electron beam with 26 MeV positron beam, or asymmetric in space, e.g., 10 GeV electron and positron beams collisions separated with a angle around 0.05 radius. Such proposals should be able to be achieved with a reasonable budget. The other type of method is relying on TeV positron on target experiment, where Kaon beams can be achieved at around $10^{7}$ per bunch crossing. Such Kaon beams are clean with small contamination, and can have great physics potential on, e.g., hyperon searches through Kaon nuclei collision, Kaon rare decay measurement, and Kaon proton or Kaon lepton collisions. The same technique with very asymmetric electron positron collisions can also be extended to other final states such as pions and tau leptons.

Volker Ziemann

We describe a framework to assemble permanent-magnet cubes in 3D-printed frames to construct dipole, quadrupole, and solenoid magnets, whose field, in the absence of iron, can be calculated analytically in three spatial dimensions. Rotating closely spaced dipoles and quadrupoles in opposite directions allows us to adjust the integrated strength of a multipole. Contributions of unwanted harmonics are calculated and found to be moderate. We then combine multiple magnets to construct beam-line modules: chicane, triplet cell, and solenoid focusing system.

J. Foster, H. Hall

Dongjun Wang, T. Imae

P. Antoniou, J. Hamilton, B. Koopman et al.

Susan A Carroll-Webb, J. Walther

J. Parrish, J. Susko-Parrish, N. First

Robert J. Gillies, Z. Liu, Z. Bhujwalla

A. Moore, K. R. Reddy

D. Dalgleish, A. Law

R. Wogelius, J. Walther

G. Laslett, A. McBratney, P. Pahl et al.

C. Frelin, P. Vigne, A. Ladoux et al.

S. Sauvé, Murray B. McBride, W. Hendershot

S. Saporito-irwin, C. Birse, P. Sypherd et al.

K. Németh-Cahalan, James E. Hall

W. Wurts, R. Durborow

J. N. Butler