BELOV A.

In this work we present a hybrid detection method providing simultaneous imaging and timing information suitable for fully monitoring positronium (Ps) formation, its laser excitation, and its spatial propagation for the first trials of pulsed antihydrogen (H) production through a charge-exchange reaction with trapped antiprotons (p). This...

We characterized the pulsed Rydberg-positronium production inside the Antimatter Experiment: Gravity, Interferometry, Spectroscopy (AEg¯IS) apparatus in view of antihydrogen formation by means of a charge exchange reaction between cold antiprotons and slow Rydberg-positronium atoms. Velocity measurements on the positronium along two axes in a...

In this contribution, the system of the external plastic scintillator slabs of the AEgIS experiment is presented. These slabs, surrounding the superconducting magnet and operating at room temperature, are read out by photomultiplier tubes (PMTs) that are calibrated and equalised to be exploited as a whole detector with useful segmentation and...

The foreseen production of cold antihydrogen atoms at CERN's Antiproton Decelerator (AD) opened up the possibility to perform direct measurements of Earth's gravitational acceleration on antimatter bodies. This is one of the goals of the AEgIS collaboration: measure the value of g using a pulsed source of cold antihydrogen and a moiré...

We investigate experimentally the possibility of enhancing the production of 2S3 positronium atoms by driving the 1S3-3P3 and 3P3-2S3 transitions, overcoming the natural branching ratio limitation of spontaneous decay from 3P3 to 2S3. The decay of 3P3 positronium atoms toward the 2S3 level has been efficiently stimulated by a 1312.2 nm...

In this work we describe a high-resolution position-sensitive detector for positronium. The detection scheme is based on the photoionization of positronium in a magnetic field and the imaging of the freed positrons with a Microchannel Plate assembly. A spatial resolution of (88±5) μm on the position of the ionized positronium –in the plane...

Antihydrogen atoms with K or sub-K temperature are a powerful tool to precisely probe the validity of fundamental physics laws and the design of highly sensitive experiments needs antihydrogen with controllable and well defined conditions. We present here experimental results on the production of antihydrogen in a pulsed mode in which the time...

The AE¯ gIS collaboration's main goal is to measure the acceleration of antihydrogen (H¯ ) due to gravity. The experimental scheme is to form a pulsed beam whose vertical deflection is then measured by means of a moiré deflectometer [1]. Creating pulsed H¯ is crucial since it allows a velocity measurement of the antiatoms via time of flight...

Positronium in the 2S3 metastable state exhibits a low electrical polarizability and a long lifetime (1140 ns), making it a promising candidate for interferometry experiments with a neutral matter-antimatter system. In the present work, 2S3 positronium is produced, in the absence of an electric field, via spontaneous radiative decay from the...

A main scientific goal of the AEgIS ¯ experiment is the direct measurement of the Earth's local gravitational acceleration g on antihydrogen. The Weak Equivalence Principle is a foundation of General Relativity. It has been extensively tested with ordinary matter but very little is known about the gravitational interaction between matter and...

Cold antihydrogen atoms are a powerful tool to probe the validity of fundamental physics laws, and it's clear that colder atoms, generally speaking, allow an increased level of precision. After the first production of cold antihydrogen (H in 2002 [1], experimental efforts have progressed continuously (trapping [2], beam formation [3],...

We present the commissioning of the Fast Annihilation Cryogenic Tracker detector (FACT), installed around the antihydrogen production trap inside the 1T superconducting magnet of the AEgIS experiment. FACT is designed to detect pions originating from the annihilation of antiprotons. Its 794 scintillating fibers operate at 4K and are read out by...

The 33P state of positronium is an intermediate level suitable for producing long-lived positronium states. On one hand, it can be used in a two-step laser excitation scheme from the ground state to Rydberg levels. On the other hand, excitation of positronium to 33P level is a simple pathway for producing metastable 23S positronium atoms by...

Studies of antimatter are important for understanding our universe at a fundamental level. There are still unsolved problems, such as the matter-antimatter asymmetry in the universe. The AEgIS experiment at CERN aims at measuring the gravitational fall of antihydrogen in order to determine the gravitational force on antimatter. The proposed...

Producing positronium (Ps) in the metastable 23S state is of interest for various applications in fundamental physics. We report here on an experiment in which Ps atoms are produced in this long-lived state by spontaneous radiative decay of Ps excited to the 33P level manifold. The Ps cloud excitation is obtained with a UV laser pulse in an...

AEgis (Antimatter Experiment: Gravity, Interferometry, Spectroscopy) is a CERN based experiment aiming to probe the Weak Equivalence Principle of General Relativity with antimatter by studying free fall of antihydrogen in the Earthfs gravitational field. A pulsed cold beam of antihydrogen produced by charge exchange between Rydberg positronium...

Forming a pulsed beam of cold antihydrogen using charge-exchange with Rydberg positronium (Ps) is the goal of the AE?IS collaboration, which aims to a first gravity measurement on neutral antimatter. Recently achieved results in Ps formation and laser spectroscopy in the main AE?IS apparatus are summarized. First, Ps has been produced using...