arXiv subjects

M. Peng

Publications and source records attributed to M. Peng.

6 recordsLinked to original sources

arXiv2023

Using the Sun and the Moon as Source masses and the Earth's Rotation as a Modulation to Search for Exotic Spin-Dependent Interactions at Astronomical Distances

Exotic spin-dependent interactions mediated by new light particles led to solutions to several important questions in modern physics. Such interactions involving a scalar coupling $g_S^N$ at one vertex and a pseudo-scalar coupling $g_P^n$ at the polarized neutron vertex can be induced by the exchange of spin-0 bosons, or a vector/axial-vector coupling $g_V^N$/$g_A^N$ at one vertex and an axial-vector coupling $g_A^n$ at the polarized neutron vertex can be induced by the exchange of spin-1 bosons. If such new interactions exist, the Sun and the Moon can induce sidereal variations of effective fields along the direction perpendicular to the Earth's rotation axis. We derived new experimental upper limits on such exotic spin-dependent interactions at astronomical interaction ranges by analyzing existing data from laboratory measurements on the Lorentz and CPT violation. We set the most stringent experimental limits on $g_S^Ng_P^n$ ranging from $\sim 2\times 10^{10}$m to $\sim 10^{14}$m. Previously, the best limit on $g_S^Ng_P^n$ at this range is from astrophysics. The result is the first time laboratory limits surpass the astrophysical ones on the scalar-pseudoscalar type interaction, to our best knowledge. We report new constraints on vector-axial-vector and axial-axial-vector type interaction at the range of astronomical scales. The new limits on vector-axial-vector are improved by as much as $\sim$12 orders of magnitude. We also apply the analysis to the Hari-Dass interactions and obtain corresponding new constraints on the interactions. We discuss the possibilities of using the beam method to further search the interaction involving other particles, such as electrons, muons, etc., based on the same idea.

hep-ph↗

arXiv2021

New Experimental Limits on Exotic Spin- and Velocity-dependent Interactions Using Rotationally Modulated Source-masses and an Atomic-magnetometer Array

We conducted laboratory searching for the exotic spin- and velocity-dependent new interactions according to the previously proposed experimental scheme. Two $\sim$6Kg heavy source masses are rotationally modulated at a frequency of 20Hz. Four identical atomic magnetometers are used in an array form to increase the statistics and cancel the common-mode noise. Data processing method based on high precision numerical integration is applied for the four harmonic frequencies of the signal. The rotation direction of the source masses was reversed to flip the signal. Thus the [1,-3,3,-1] weighting method can be applied to remove possible slow drifting further. The experiment method has noise reduction features, and new constraints for Vector-Axial and Axial-Axial were obtained. The new constraints on VA improved by as much as more than four orders, on AA by as much as two orders in the corresponding force range, respectively.

nucl-ex↗

arXiv2021

Searching for Exotic Spin-Dependent Interactions Using Rotationally Modulated Source Masses and an Atomic Magnetometer Array

We describe a proposed experimental search for exotic spin-dependent interactions using rotationally modulated source masses and an atomic magnetometer array. Rather than further improving the magnetometer sensitivity, noise reduction can be another way to reach higher measurement precision. In this work, we propose to use modulating techniques of the source masses to reduce the noise of the experiment. Better precision can be achieved if the fundamental frequency and harmonics of the rotating source masses are used to detect the new interactions. Furthermore, if an array of magnetometers are applied, the statistic precision can be improved, and some common noises can be canceled. Our analysis and simulations indicate that the proposed experiment scheme can improve the detection precisions of three types of spin-dependent interactions by as much as $\sim$5 orders in the force range of $\sim$cm to $\sim$10m.

hep-ex↗

arXiv2018

Constraining New Muonic Interactions Meditated by Axion-Like-Particles

ALPs (Axion Like Particle) beyond the standard model are solutions to several important problems of modern physics. One way to detect these particles is to detect the new interactions they meditate. Many experiments have been performed to search for these new interactions in ranges from $\sim\mu$m to astrophysical range. At present, nearly all known experiments searching for the ALP-meditated long range new interactions use sources or probes containing protons, neutrons and electrons. Constraints for other fermions such as muons are scarce, though muons might be the most suspicious particles which could take part in new interactions, considering their involvement of several well known puzzles of modern physics. In this work, we discuss the possibility of explaining the anomalous magnetic moment of muons by the long range muonic new interactions mediated by ALPs. We also give a constraint for the scalar-pseudo-scalar(SP) type interaction meditated by muonic ALPs. We propose to further search the muonic SP type interaction by muon spin rotation experiments.

hep-ph↗

arXiv2015

Fronthaul-Constrained Cloud Radio Access Networks: Insights and Challenges

As a promising paradigm for fifth generation (5G) wireless communication systems, cloud radio access networks (C-RANs) have been shown to reduce both capital and operating expenditures, as well as to provide high spectral efficiency (SE) and energy efficiency (EE). The fronthaul in such networks, defined as the transmission link between a baseband unit (BBU) and a remote radio head (RRH), requires high capacity, but is often constrained. This article comprehensively surveys recent advances in fronthaul-constrained C-RANs, including system architectures and key techniques. In particular, key techniques for alleviating the impact of constrained fronthaul on SE/EE and quality of service for users, including compression and quantization, large-scale coordinated processing and clustering, and resource allocation optimization, are discussed. Open issues in terms of software-defined networking, network function virtualization, and partial centralization are also identified.

cs.IT↗

arXiv2015

Long Pulse EBW Start-up Experiments in MAST

The non-solenoid start-up technique reported here relies on a double mode conversion for electron Bernstein wave (EBW) excitation. It consists of the mode conversion of the ordinary mode, entering the plasma from the low field side of the tokamak, into the extraordinary (X) mode at a mirror-polarizer located at the high field side. The X mode propagates back to the plasma, passes through electron cyclotron resonance and experiences a subsequent X to EBW mode conversion near the upper hybrid resonance. Finally the excited EBW mode is totally absorbed at the Doppler shifted electron cyclotron resonance. The absorption of EBW remains high even in cold rarefied plasmas. Furthermore, EBW can generate significant plasma current giving the prospect of a fully solenoid-free plasma start-up. First experiments using this scheme were carried out on MAST [V. Shevchenko et al, Nuclear Fusion 50, 022004 (2010)]. Plasma currents up to 33 kA have been achieved using 28 GHz 100kW 90ms RF pulses. Recently experimental results were extended to longer RF pulses showing further increase of plasma currents generated by RF power alone. A record current of 73kA has been achieved with 450ms RF pulse of similar power. The current drive enhancement was mainly achieved due to RF pulse extension and further optimisation of the start-up scenario.

physics.plasm-ph↗