Scientific Commons: Gerhard Backenstoss

LEAR offered unique opportunities to study the symmetries which exist between matter and antimatter. At variance with other approaches at this facility, CPLEAR was an experiment devoted to the study...

Physics at CPLEAR (2003)

Angelopoulos, A., Apostolakis, A., Aslanides, E., Backenstoss, Gerhard., Bargassa, P., Bee, C.P., ...

LEAR offered unique opportunities to study the symmetries which exist between matter and antimatter. At variance with other approaches at this facility, CPLEAR was an experiment devoted to the study...

$T$-violation and $CPT$-invariance measurements in the CPLEAR experiment: a detailed description of the analysis of neutral-kaon decays to $e\pi\nu$ (2001)

Angelopoulos, Angelos, Aslanides, Elie, Backenstoss, Gerhard, Bargassa, P, Behnke, O, Benelli, A, ...

A detailed description of the analysis of neutral kaons decaying to \pen\ is given, based on the complete set of data collected with the CPLEAR experiment. Using a novel approach involving initially...

A detailed description of the analysis of the decay of neutral kaons to $\pi^+ \pi^-$ in the CPLEAR experiment (2000)

Apostolakis, Alcibiades J, Aslanides, Elie, Backenstoss, Gerhard, Bargassa, P, Behnke, O, Benelli, A, ...

A detailed description is given of the analysis of neutral kaons decaying to \pipi , based on the complete data sample collected with the CPLEAR experiment.Using a novel approach involving initially...

Measurement of the energy dependence of the form factor $f_{+}$ in $K^{0}_{e3}$ decay (1999)

Apostolakis, Alcibiades J, Aslanides, Elie, Backenstoss, Gerhard, Bargassa, P, Behnke, O, Benelli, A, ...

Neutral-kaon decays to \pielnu\ % recorded by the CPLEAR experimentwere analysed to determine the $q^2$ dependence of the \Kzet\ electroweak form factor $f_+$. Based on $365\,612$ events,this form...

Dispersion relation analysis of the neutral kaon regeneration amplitude in carbon (1999)

Angelopoulos, Angelos, Apostolakis, Alcibiades J, Locher, M P, Markushin, V E, Aslanides, Elie, Backenstoss, Gerhard, ...

We apply a forward dispersion relation to the regeneration amplitude for kaon scattering on /sup 12/C using all available data. The CPLEAR data at low energies allow the determination of the net...

$K^{0}-\overline{K}^{0}$ mass and decay-width differences: CPLEAR evaluation (1999)

Angelopoulos, Angelos, Apostolakis, Alcibiades J, Aslanides, Elie, Backenstoss, Gerhard, Bargassa, P, Behnke, O, ...

The CPT-violation parameters \redd\ and \imd\ determined recently by CPLEAR are used to evaluate the \kn --\knb\ mass and decay-width differences, as given by the difference between the diagonal...

A determination of the CP violation parameter $\eta_{+-}$ from the decay of strangeness-tagged neutral kaons (1999)

Apostolakis, Alcibiades J, Aslanides, Elie, Backenstoss, Gerhard, Bargassa, P, Behnke, O, Benelli, A, ...

We report a measurement of the CP violation parameter $\eta$ from the time-dependent asymmetry between the decay rates of initially tagged \kn\ and \knb . The results are based on the complete data...

Determination of the T- and CPT-violation parameters in the neutral-kaon system using the Bell-Steinberger relation and data from CPLEAR (1999)

Apostolakis, Alcibiades J, Aslanides, Elie, Backenstoss, Gerhard, Bargassa, P, Behnke, O, Benelli, A, ...

Data from the CPLEAR experiment, together with the most recent world averages for some of the neutral-kaon parameters, were constrained with the Bell--Steinberger (or unitarity) relation, allowing...

Tests of the equivalence principle with neutral kaons (1999)

Apostolakis, Alcibiades J, Aslanides, Elie, Backenstoss, Gerhard, Bargassa, P, Behnke, O, Benelli, A, ...

We test the Principle of Equivalence for particles and antiparticles, using CPLEAR data on tagged Pkao and Pkab decays into $pi^+ pi^-$. For the first time, we search for possible annual, monthly and...

Total cross sections of the charge exchange reaction$(\pi^{+},\pi^{0})$ on $^{2}H, ^{3}He$ and $^{4}He,$ across the $\Delta(1232)$ resonance (1999)

Lehmann, A, Androic, D, Backenstoss, Gerhard, Bosnar, D, Dooling, T, Furic, M, ...

First direct observation of time-reversal non-invariance in the neutral-kaon system (1998)

Angelopoulos, A, Apostolakis, Alcibiades J, Aslanides, Elie, Backenstoss, Gerhard, Bargassa, P, Behnke, O, ...

We report on the first observation of time-reversal symmetry violation through a comparison of the probabilities of $\knb$ transforming into $\kn$ and $\kn$ into $\knb$ as a function of the...

Measurement of the $K_{L}-K_{S}$ mass difference using semileptonic decays of tagged neutral kaons (1998)

Angelopoulos, Angelos, Apostolakis, Alcibiades J, Aslanides, Elie, Backenstoss, Gerhard, Bargassa, P, Behnke, O, ...

We report on a new measurement of the \kl--\ks\ mass difference \dm\ using the CPLEAR full data sample of neutral-kaon decays to \semi. The result is $\dm = (0.5295 \pm 0.0020_{\stat} \pm...

A determination of the CPT violation parameter Re($\delta$) from the semileptonic decay of strangeness-tagged neutral kaons (1998)

Angelopoulos, Angelos, Apostolakis, Alcibiades J, Aslanides, Elie, Backenstoss, Gerhard, Bargassa, P, Behnke, O, ...

We have improved by two orders of magnitude the limit currently available for the CPT violation parameter \red . To this purpose we have analyzed the full sample of neutral-kaon decays to \semi\...

First direct observation of time-reversal non-invariance in the neutral-kaon system (1998)

Angelopoulos, Angelos, Apostolakis, Alcibiades J, Aslanides, Elie, Backenstoss, Gerhard, Bargassa, P, Behnke, O, ...

We report on the first observation of time-reversal symmetry violation through a comparison of the probabilities of $\knb$ transforming into $\kn$ and $\kn$ into $\knb$ as a function of the...

The neutral kaon decays to ${\pi^+ \pi^- \pi^0$}: a detailed analysis of the CPLEAR data (1998)

Angelopoulos, Angelos, Apostolakis, Alcibiades J, Aslanides, Elie, Backenstoss, Gerhard, Bargassa, P, Behnke, O, ...

A detailed analysis of neutral kaons decaying to \Pgpp \Pgpm \Pgpz\ is presented based on the complete data set containing half a million events. Time-dependent decay rate asymmetries are measured...

Initial state interaction in the $(\pi^{+},3p)$ reaction on N, Ar and Xe (1998)

Kotlínski, B, Androic, D, Backenstoss, Gerhard, Bosnar, D, Breuer, H, Döbbeling, H, ...

Search for CP violation in the decay of tagged $\overline{K}^0$ and $K^0$ to $\pi^{0}\pi^{0}\pi^{0}$ (1998)

Angelopoulos, Angelos, Apostolakis, Alcibiades J, Aslanides, Elie, Backenstoss, Gerhard, Bargassa, P, Behnke, O, ...

The CPLEAR experiment measured the eigentime-dependent asymmetry in the rates of initially tagged \kzerob\ and \kzero\ decaying to \threepizero\ in order to study the interference between the...

Measurement of the CP-violation parameter $\eta_{00}$ using tagged $\overline{K^{0}}$ and $K^{0}$ (1997)

Angelopoulos, Angelos, Apostolakis, Alcibiades J, Aslanides, Elie, Backenstoss, Gerhard, Bargassa, P, Behnke, O, ...

The CP-violation parameter \etazero\ is determined through the eigentime-dependent asymmetry in the rates of initially tagged \kzerob\ and \kzero\ decaying to \pizero \pizero. From the analysis of...

An EPR experiment testing the non-separability of the $K^{0} \overline{K^{0}}$ wave function (1997)

Apostolakis, Alcibiades J, Aslanides, Elie, Backenstoss, Gerhard, Bargassa, P, Behnke, O, Benelli, A, ...

The EPR-type strangeness correlation in the \PKz \PaKz ~system produced in the reaction $\Pap \Pp \rightarrow \PKz \PaKz$ at rest has been tested using the CPLEAR detector. The strangeness was tagged...

Direct determination of two-pion correlations for $\overline{p}p \to 2\pi^{+}2\pi^{-}$ annihilation at rest (1997)

Angelopoulos, Angelos, Apostolakis, Alcibiades J, Aslanides, Elie, Backenstoss, Gerhard, Bargassa, P, Behnke, O, ...

We study $\pi\pi$ correlations in the exclusive reaction $\ppb \to 2\pi^+2\pi^-$ at rest measured by the CPLEAR experiment. Avoiding the introduction of an arbitrary reference sample, we analyse...

Measurement of the neutral kaon regeneration amplitude in carbon at momenta below 1 GeV/c (1997)

Angelopoulos, Angelos, Apostolakis, Alcibiades J, Aslanides, Elie, Backenstoss, Gerhard, Bargassa, P, Behnke, O, ...

The neutral kaon regeneration amplitude in carbon at momenta between 250 and 750~MeV/$c$ was determined by measuring the interference of inherent and coherently regenerated \PKS\ amplitudes. This...

Multinucleon pion absorption on $^{4}He$ into the pppn final state (1997)

Lehmann, A, Androic, D, Backenstoss, Gerhard, Bosnar, D, Breuer, H, Döbbeling, H, ...

CPLEAR results on the CP parameters of neutral kaons decaying to $\pi^+ \pi^- \pi^0$ (1997)

Adler, R, Angelopoulos, Angelos, Apostolakis, Alcibiades J, Aslanides, Elie, Backenstoss, Gerhard, Bargassa, P, ...

The CPLEAR experiment measured time-dependent decay-rate asymmetries of \PKz\ and \PaKz\ decaying to \pipmz\ in order to study the interference between the decay amplitudes of \PKzS\ --- either...

Atomic systems of muons and hadrons: Convener's Report Group 2 (1997)

Backenstoss, Gerhard

Pion absorption on $^{3}He$ and $^{4}He$ with emission of three energetic protons (1997)

Lehmann, A, Androic, D, Backenstoss, Gerhard, Bosnar, D, Breuer, H, Döbbeling, H, ...

The CPLEAR Electromagnetic Calorimeter (1997)

Adler, R, Backenstoss, Gerhard, Bal, F, Behnke, O, Bloch, P, Damianoglou, D, ...

A large-acceptance lead/gas sampling electromagnetic calorimeter (ECAL) was constructed for the CPLEAR experiment to detect photons from decays of $\pi^0$s with momentum $p_{\pi^0} \le 800$ MeV$/c$....

Contribution of CPLEAR to the physics of the neutral kaon system (1997)

Pavlopoulos, P, Adler, R, Alhalel, T, Angelopoulos, Angelos, Apostolakis, Alcibiades J, Aslanides, Elie, ...

We present the physics results of the CP-- and CPT--violation measurements performed by CPLEAR. CPLEAR has experimentally determined for the first time, the violation of T invariance and is able to...

The CPLEAR detector at CERN (1996)

Adler, R, Albrecht, W, Alhalel, T, Angelopoulos, Angelos, Apostolakis, Alcibiades J, Aslanides, Elie, ...

The CPLEAR collaboration has constructed a detector at CERN for an extensive programme of CP-, T- and CPT-symmetry studies using ${\rm K}^0$ and $\bar{\rm K}^0$ produced by the annihilation of...

A large acceptance detector system (LADS) for studies of pion absorption (1996)

Alteholz, T, Androic, D, Backenstoss, Gerhard, Bosnar, D, Breuer, H, Brkovic, A, ...

Evidence of initial state interactions in multi-nucleon pion absorption (1996)

Androic, D, Backenstoss, Gerhard, Bosnar, D, Breuer, H, Döbbeling, H, Dooling, T, ...

Observation of the CP-conserving K$_{S}$ --> $\pi^{+}\pi^{- }\pi^{0}$ decay amplitude (1996)

Adler, R, Alhalel, T, Angelopoulos, Angelos, Aspostolakis, A, Aslanides, Elie, Backenstoss, Gerhard, ...

The interference between CP-conserving $\ks$ and $\kl \rightarrow \threepi$ decay amplitudes was observed by studying the decay rate asymmetries between initial $\ko$ and $\kob$ separately for the...

Contribution of initial state interactions to the three-nucleon absorption of pions by $^{3}$He (1996)

Backenstoss, Gerhard, Bosnar, D, Breuer, H, Döbbeling, H, Dooling, T, Furic, M, ...

Search for CP-violation in the decay of neutral kaons to $\pi^{+}\pi^{- }\pi^{0}$ (1996)

Adler, R, Alhalel, T, Angelopoulos, Angelos, Apostolakis, Alcibiades J, Aslanides, Elie, Backenstoss, Gerhard, ...

The time-dependent rate asymmetry of initial \ko and \kob decaying into \threepi was measured in order to reveal the CP-violating amplitude of the \ks \rightarrow \threepi decay. For the real and the...

Test of CPT symmetry and quantum mechanics with experimental data from CPLEAR (1995)

Adler, R, Angelopoulos, Angelos, Apostolakis, Alcibiades J, Aslanides, Elie, Backenstoss, Gerhard, Bee, C P, ...

We use fits to recent published CPLEAR data on neutral kaon decays to \pi^+\pi^- and \pi e\nu to constrain the CPT--violation parameters appearing in a formulation of the neutral kaon system as an...

First observation of a particle-antiparticle asymmetry in the decay of neutral kaons into $\pi^{0}\pi^{0}$ (1995)

Adler, R, Alhalel, T, Angelopoulos, Angelos, Apostolakis, Alcibiades J, Aslanides, Elie, Backenstoss, Gerhard, ...

A new determination of the K$_{L}$ - K$_{S}$ mass difference and the phase of the CP violation parameter $\eta_{\pm}$ from an evaluation of experimental data (1995)

Adler, R, Angelopoulos, Angelos, Apostolakis, Alcibiades J, Aslanides, Elie, Backenstoss, Gerhard, Bee, C P, ...

Measurement of the CP violation parameter $\eta_{\pm}$ using tagged K$^{0}$ and $\overline{K}^{0}$ (1995)

Adler, R, Alhalel, T, Angelopoulos, Angelos, Apostolakis, Alcibiades J, Aslanides, Elie, Backenstoss, Gerhard, ...

Measurement of K$_{L}$-K$_{S}$ mass difference using semileptonic decays of tagged neutral kaons (1995)

Adler, R, Alhalel, T, Angelopoulos, Angelos, Apostolakis, Alcibiades J, Aslanides, Elie, Backenstoss, Gerhard, ...

Experimental tests of CPT symmetry and quantum mechanics at CPLEAR (1995)

Mavromatos, Nikolaos E, Ellis, Jonathan Richard, López, J L, Nanopoulos, Dimitri V, Adler, R, Alhalel, T, ...

We review a phenomenological parametrization of an open quantum-mechanical formalism for CPT violation in the neutral kaon system, and constrain the parameters using fits to recent CPLEAR data.

The study of the CP, T and CPT symmetries in the CPLEAR experiment (1994)

Yéche, C, Adler, R, Alhalel, T, Angelopoulos, Angelos, Apostolakis, Alcibiades J, Aslanides, Elie, ...

Inclusive measurement of $\overline{p}$ annihilation at rest in gaseous hydrogen to final states containing $\varrho$ and f$_{2}$ (1994)

Adler, R, Alhalel, T, Angelopoulos, Angelos, Apostolakis, Alcibiades J, Aslanides, Elie, Backenstoss, Gerhard, ...

Bose-Einstein correlations in $\overline{p}$p annihilations at rest (1994)

Adler, R, Alhalel, T, Angelopoulos, Angelos, Apostolakis, Alcibiades J, Aslanides, Elie, Backenstoss, Gerhard, ...

Design and test of a prototype gas-sampling electromagnetic calorimeter of high granularity for the CPLEAR experiment (1992)

Adler, R, Backenstoss, Gerhard, Bloch, P, Damianoglou, D, Dechelette, Paul, Dröge, M, ...

First determination of CP violation parameters from K$^{0}$ - $\overline{K}^{0}$ decay asymmetry (1992)

Adler, R, Alhalel, T, Angelopoulos, Angelos, Apostolakis, Alcibiades J, Aslanides, Elie, Backenstoss, Gerhard, ...

First results from CP-LEAR: study of CP-violation and CPT tests using K$^{0}$-$\overline{K}^{0}$ interferometry (1991)

Adler, R, Alhalel, T, Angelopoulos, Angelos, Apostolakis, Alcibiades J, Aslanides, Elie, Backenstoss, Gerhard, ...