Heavy Liquid Bubble Chamber Research Articles

From Gargamelle to MINERvA: exploring the structure of the nucleon with neutrinos

Neutrino scattering experiments have been exploring the structure of the nucleon with Deep-Inelastic Scattering for over 50 years. Although hints of nucleon structure were available using CERN’s first neutrino beam in the 1960s, the study actually started quantitatively in the early 1970s with the Gargamelle heavy liquid bubble chamber that produced first neutrino confirmation of scaling. This study of nucleon structure continued with both bubble chambers and more massive electronic detectors that, with higher energy neutrino beams and \(Q^2\) reach, examined the breaking of this scaling while testing Quantum Chromodynamics. A significant factor when including neutrino explorations of nucleon structure in the overall picture is that to gather significant statistics, neutrino experiments have had to use heavier nuclear targets. It has been experimentally demonstrated that the structure of the nucleon in the nuclear environment is indeed different than the free nucleon structure. Understanding this modified structure has played an important part in the experimental and theoretical exploration of nucleon structure by neutrinos and is one of the important goals of the on-going MINERvA experiment at Fermilab.

André Lagarrigue: From cosmic rays to the discovery of the weak neutral currents

Abstract Andre Lagarrigue's scientific career is intimately related to the development of elementary particle physics, from pioneering studies with cosmic rays to the discovery of weak neutral currents. His experience in building detectors, culminating with the construction of large heavy liquid bubble chambers, his vision of the best experimental paths, and his enthusiastic leadership have strongly contributed to the progress of the field. The discovery of weak neutral currents with the giant Gargamelle bubble chamber was the first major step in establishing the Standard Model of the fundamental interactions based on gauge theories.

Martin Moses Block

Martin Moses Block

New approaches to dark matter and neutrino detection

Two new initiatives in astroparticle and neutrino physics are briefly reviewed. COUPP employs ultra-stable heavy liquid bubble chambers to search for WIMP dark matter. First results leading to improved limits on spin-dependent WIMP couplings are presented, together with the most recent progress and prospects. CoGeNT aims at the detection of very faint (∼100 eV) signals in detectors massive enough (∼1 kg) to allow searches for rare processes, using recently developed p-type point contact (PPC) germanium detectors. The broad range of applications (coherent neutrino scattering, light WIMP searches, double-beta decay) for these semiconductor devices is succinctly described. The implications from their first underground operation are discussed, as well as the status of an ongoing deployment at the San Onofre nuclear generation plant.

A bubble chamber for dark matter detection (the COUPP project status)

Heavy-liquid bubble chambers can be made stable-enough to be used in searches for Weakly Interacting Massive Particles (WIMPs). Advantages of this approach are optimal choice of target liquid-CF3I, maximally sensitive to both spin-dependent (SD) and spin-independent (SI) WIMP interactions, low cost, good scalability, room temperature operation, extraordinary intrinsic rejection of minimally-ionizing backgrounds, and a number of features permitting rejection of irreducible neutron backgrounds. A 2 kg prototype chamber is currently operating at the depth of 300 meters water equivalent (m.w.e.) NuMi gallery of Fermilab. Even with the small prototype mass, results competitive in the SI channel and surpassing current limits in the SD channel are expected.

The discovery of weak neutral currents

The discovery of weak neutral currents was performed by an European collaboration using Gargamelle at CERN. This discovery was the culmination of the development of heavy liquid bubble chambers in Europe beginning with Ecole Polytechnique chambers.

Study of 360 GeV/c proton-nucleus interactions using CERN holographic bubble chamber

The study of high-energy proton-nucleus collisions is done with a holographic film from the exposure of CERN heavy liquid bubble chamber (HOBC) to a 360 Ge V/c proton beam. The multiplicity, the pseudorapidity distributions of its secondary charged particles and their correlations are analysed and compared with those of some Monte Carlo event generators. Results suggest that the multichain model including the concept of formation zone is suitable to reproduce our experimental data. It is found that the intranuclear cascade process is important in order to describe the production mechanism, especially in the backward hemisphere, of high-energy proton-nucleus collisions.

Momentum measurements of electrons in a heavy-liquid bubble chamber

The momentum reconstruction of high-energy electrons in a heavy-liquid bubble chamber is studied using Monte Carlo simulations. The energies of the simulated electrons used in this study ranged from 10 to 100 GeV. The angular distribution and multiplicity of converted bremsstrahlung gammas is given as a function of energy for these events. An energy-independent method of correcting for poor measurements due to hard bremsstrahlung is found. This method consists of summing the reconstructed electron momentum and the momentum of the highest energy converted gamma.

A new method to investigate the nuclear effect in leptonic interactions

High energy neutrino interactions in a heavy liquid bubble chamber were classified by the presence or absence of dark tracks (stubs) at the interaction vertices. Quark distributions, σ( x), were compared in the two groups of data. Those with dark tracks, presumably indicative of an interaction with a deeply bound nucleon, show an enhanced nuclear effect.

New experimental limits on νμ→ νe oscillations

The results of an experiment which searched for ν e events arising from oscillations of a low-energy ν μ beam are presented. The BEBC heavy liquid bubble chamber, placed at a distance of 825 m from an external proton target at the CERN PS, was used as a neutrino detector. The appearance of ν e CC interactions provides a sensitive indication of ν μ → ν e oscillations. 470 ν μ CC events and 4 ν e events, with an estimated background of 3 ν c CC events, have been observed. The resulting limits on the oscillation parameters are: δm 2⩽0.09 eV 2 (for maximal mixing) and sin 2 θ⩽0.013 for δm 2=2.2 eV 2, at the 90% confidence level.

A Measurement of the Total Charm Cross Section in 200 and 360 GeV/c pN Interactions Using a Holographic Bubble Chamber

We present results from the first holographic bubble chamber experiment. Using topological information on the events observed in the heavy liquid bubble chamber HOBC, we have determined a total charm pair production cross section of (24.6-8.3+12.0) μb and (3.9-1.9+2.5) μb in 360 GeV/c and 200 GeV/c proton-nucleon interactions respectively. For these estimates we assumed a linear dependence of the charm cross section on the atomic number A.

The HOLMES project

HOLMES is a working prototype of a scanning and measuring machine for in-line holograms of HOBC heavy liquid bubble chamber events.

On the measurement of the momentum of 19 GeV/ c electrons in a heavy liquid bubble chamber

The Fermilab 15-ft bubble chamber was exposed to an electron beam of 19 GeV/ c momentum. The chamber was filled with a heavy neon-hydrogen mixture (64% atomic Ne, 36% atomic H) and operated with a magnetic field of 3 T. The momentum of the electrons was determined from the bubble chamber pictures using two methods: (a) the measurement of the curvature of the electrons and their shower products, and (b) the measurement of the total track length of the electron and its shower. The momentum, as determined from curvature measurement of the primary electron and the e +e − pairs from the radiated gammas was 19.1±7.6 GeV/c.

Search for charmed particles with the heavy liquid bubble chamber BIBC

In a search for short lived particles with a high resolution C 3F 8 bubble chamber and a streamer chamber, 21 charmed meson candidates produced by 340 GeV cπ − have been identified. The cross section for associated charm production is (28±11) μb per nucleon assuming a linear A-dependence. The mean lifetimes of the D mesons in units of 10 −13 s are τ( D 0, D ̄ 0) = 4.1 −1.3 +2.6 ± 0.5, τ( D ±) = 6.3 −2.3 4.8 ± 1.5 .

Performance of the holographic bubble chamber HOBC

The small holographic heavy liquid bubble chamber HOBC has been used in particle beams at the CERN PS and SPS. Under realistic data taking conditions bubble diameters of 12 μm and bubble densities around 200 per centimeter were obtained. The greatest difficulty was to obtain stable running conditions at high repetition rates and high beam fluxes.

Holographic photography of bubble chamber tracks: A feasibility test

The use of holography should permit the improvement of optical resolution in bubble chambers without the loss of depth of field inherent in conventional photography, and should also permit the use of much more intense particle beams in bubble chambers. Holographic techniques have been applied to a small heavy liquid bubble chamber in the conditions of a particle physics experiment and a resolution of 8 μm over a depth of field of some 10 cm has been obtained, yielding a reconstructed image of very high quality. 6 μm bubbles have also been reconstructed but with inferior contrast and quality. Various tests have been performed in order to determine some limitations of the method.

An experimental study of the antineutron-light nucleus annihilation at 1.4 GeV/c

The heavy liquid bubble chamber, Gargamelle, has been used to investigate the gross features of the annihilation of antineutrons in light nuclei (mainly Carbon). Results are presented on the distributions of multiplicity, momentum and emission angle for charged pions and protons together with a simple model to describe them.

Antineutrino-nucleon total cross section and ratio of antineutrino cross section on neutrons and protons

On a selected sample of 2171 events, observed in the big heavy liquid bubble chamber Gargamelle at CERN, the charged current total cross section for antineutrino on nucleons has been determined up to the laboratory energy E v ̄ = 8 GeV . The total cross section is found to be a linear function of the antineutrino energy expressed by σ tot (E v ̄ ) = (0.26 ± 0.020) × 10 −38 × E v ̄ ( GeV) cm 2 . The energy dependence of 〈q 2〉 v ̄ is found to be given by 〈q 2〉 v ̄ = (0.15 ± 0.04)E v ̄ + (0.05 ± 0.12) ( GeV/c) 2 . With a simplified nuclear model the ratio of cross sections on neutrons andprotons has been estimated as a function of energy and for two different values of the scaling variable x. The results are compared with the prediction of the naive quark parton model.

Total cross sections for v e and [formula omitted] interactions and search for neutrino oscillations and decay

About 200 and 60 candidates for electron neutrino and antineutrino interactions, respectively, have been analyzed in the heavy liquid bubble chamber Gargamelle exposed to the CERN PS neutrino beam. Evidence for scaling has been found for these interactions, with slopes of the cross sections in good agreement with those obtained for muon neutrino and antineutrino events in the same chamber. No evidence appears for oscillations of neutrinos or antineutrinos, which would induce in the present experiment an excess of electron or positron events. The corresponding limits are given as functions of the mixing parameter, for the finite mass Majorana neutrinos. The possibility of a multiplicative law for the lepton number has also been investigated. A search for isolated electron-positron pairs revealed no excess in the forward direction, in contradiction to the expectation for muonic neutrino and antineutrino decays. The corresponding limits on the c.m. half lifetimes are given.

Measurement of the branching ratios of multi-pion final states in [formula omitted] annihilation at 1.6 GeV/ c

The final results on the pionic annihilation of 1.6 GeV/ c antiprotons on free protons in the heavy liquid bubble chamber Gargamelle are presented here. Branching ratios of the various channels (including multi-π 0 channels) as well as multiplicity distributions for charged and neutral pions are given which are for the most part compatible with the prediction of the isospin statistical model.