Methods to determine neutrino flux at low energies

We present a set of recommendations for the presentation of LHC results on searches for new physics, which are aimed at providing a more efficient flow of scientific information between the experimental collaborations and the rest of the high energy physics community, and at facilitating the interpretation of the results in a wide class of models. Implementing these recommendations would aid the full exploitation of the physics potential of the LHC.     

Experimental techniques for low energy neutrino experiments

During the past years it has become always more and more important to study solar neutrinos at low energies (below 1 MeV) in order to solve the solar neutrino problem.Measuring low energy solar neutrinos is not an easy task because of the rapidly increasing background in the sub-MeV region. Thus new experimental methods have been developed to accomplish the challenging aim.     

Inelastic neutrino scattering off stable even-even Mo isotopes at low and intermediate energies

Inelastic neutrino scattering cross sections for the even-even Mo isotopes (contents of the MOON detector at Japan), at low and intermediate electron neutrino energies (?_i≤100 MeV), are calculated. MOON is a next-generation double beta and neutrino-less double-beta-decay experiment which is also a promising facility for low-energy neutrino detection. The nuclear wave functions required in this work have been constructed in the context of the quasi-particle random phase approximation (QRPA) and the results presented refer to , , , and isotopes.     

Radon-induced surface contaminations in low background experiments

In low background experiments the reduction of all possible radioactive contaminants is a crucial point for detector construction. This is also true for the surface contaminants, either those introduced during the production of detector components or those introduced during handling, treatment or storage. One of the most critical issue in this field is the control of the contamination induced by ²²²Rn and its progenies in the environment where the detectors are assembled and stored. Radioactive atoms can stick on detector components and create a net increase of the contaminants present on their surfaces, introducing an additional—often not negligible—source of background. The reduction of this kind of contaminations can become of primary importance in the case of fully sensitive devices, like cryogenic particle detectors. In this paper the analysis on the Rn sticking factor for copper and tellurium dioxide—the two main materials used for the construction of the CUORE detector—is discussed. The diffusion of radioactive atoms inside the detector components is considered in order to evaluate the effective contribution of Rn exposure to the background counting rate of an experiment.     

Non-standard interaction effects at reactor neutrino experiments

We study non-standard interactions (NSIs) at reactor neutrino experiments, and in particular, the mimicking effects on θ₁₃${\theta }_{13}$. We present generic formulas for oscillation probabilities including NSIs from sources and detectors. Instructive mappings between the fundamental leptonic mixing parameters and the effective leptonic mixing parameters are established. In addition, NSI corrections to the mixing angles θ₁₃${\theta }_{13}$ and θ₁₂${\theta }_{12}$ are discussed in detailed. Finally, we show that, even for a vanishing θ₁₃${\theta }_{13}$, an oscillation phenomenon may still be observed in future short baseline reactor neutrino experiments, such as Double Chooz and Daya Bay, due to the existences of NSIs.     

40 MCi tritium source for experiments with low energy neutrino

The artificial tritium source of 40 MCi activity was developed for the scattering experiment to measure the electron antineutrino magnetic moment. We present R&D results which specify source design and physical parameters, its experimental effectiveness and guarantee safety during its life-cycle. Relevant technological issues are featured.     

Cosmic-ray muon and atmospheric neutrino fluxes at very high energies

Estimates of cosmic-ray muon and atmospheric neutrino fluxes at TeV energies are obtained taking into account a “prompt” production of muons and neutrinos through charmed-particle decays and a “direct” lepton-pair production through the Drell-Yan mechanism and resonances. It is found that the contribution of charmed particles to the muon flux is equal to that from the conventional sources (pion and kaon decays) at 60 TeV, and the same equality can take place at 10 and 1 TeV for muon and electron neutrinos, respectively (for particles coming to sea level in the vertical direction). This “direct” production contribution to muon and neutrino fluxes is estimated very arbitrarily, but it cannot be excluded that this contribution is equal to that from the conventional source at energies of 0.5 and 0.05 PeV for muons and muon neutrinos, respectively. Currently, the estimates of the “prompt” and the “direct” contributions to cosmic-ray muons and atmospheric neutrinos are only qualitative. This is true especially for the “direct” contribution. Nevertheless, it seems reasonable to attract attention to these potentially important sources of atmospheric muons and neutrinos.     

Deuteron photodisintegration at low energies

All presently available experimental data on deuteron photodisintegration below 40 MeV (i.e., total and differential cross sections, photon asymmetry and neutron polarization) are collected and carefully compared with the present status of the conventional theory (i.e., in the framework of mesontheoretical or semi-phenomenologicalN-N potentials including subnuclear degrees of freedom and relativistic corrections). No significant evidence for a failure of the conventional theory is found within the present experimental accuracy.Partially supported by the Deutsche Forschungsgemeinschaft (SFB 201)     

Antiproton-deuteron annihilation at low energies

Recent experimental data obtained by the OBELIX collaboration on ˉpD and ˉp⁴ He total annihilation cross sections are analyzed. The combined analysis of these data with existing antiprotonic atom data allows, for the first time, the imaginary parts of the S-wave scattering lengths for the two nuclei to be extracted. The obtained values are: Im a^sc ₀= [−0.62 ± 0.02 stat) ± 0.04 (sys)] fm for ˉpD and Im a^sc ₀= [−0.36 ± 0.03 (stat)^+0.19 _−0.11 (sys)] fm for ˉp ⁴He. This analysis indicates an unexpected behaviour of the imaginary part of the ˉp-nucleus S-wave scattering length as a function of the atomic weight A: |Im a^sc ₀| (macr;pp) > |Im a^sc ₀| (ˉpD) > |Im a^sc ₀ (ˉp⁴ He). Received: 3 November 1999 / Revised version: 15 December 1999     

Heavy-ion fusion at low energies

Through precision measurements of fusion cross sections at energies close to the Coulomb barrier and through the application of the method of “experimental barrier distributions” which these permit, many recent advances have been made in our understanding of the dynamical processes occurring during a heavy-ion collision. It is now clear that the target and projectile reach one another in superpositions of states which correspond to different orientations for rotational nuclei or to different induced deformations for vibrational nuclei. The creation of a neck of neutron matter has also long been postulated and by studying the isotopic dependence of the fusion reaction, some recent results in the ¹⁰Ca+^90,96Zr systems appear to confirm this result. For large Z ₁ Z ₂ a type of extra-push effect can arise from the same inelastic entrance-channel effects which enhance the fusion of lighter systems, though this will be absent in cases where the enhancement arises from neutron transfers. The existence of different barriers will of course influence all other reaction channels. Fusion simply allows one to visualise the barriers most easily, since for this process, the total cross section is an incoherent sum of the contributions from all relevant eigenchannels. Some effects in other channels have already been observed. Other possible effects will be discussed. These include; the exploitation of the lowest-energy barrier to produce exotic evaporation residues and strongly deformed high-spin states at low excitation energy.     

Hadron physics at low energies

Understanding how quantum chromodynamics, the theory of strong interaction, works in the low-energy region, the so-called confinement region is one of the major challenges facing physicists. Low energy hadron physics, particularly the structure of hadron is one of the most active areas of research in nuclear physics addressing this challenge. In this talk, I will review advances made in this area on a few selected topics in the last decade or so and also provide outlook for the future.     

Hydrogen-antihydrogen interactions at low energies

The main cause of loss of trapped AH is due to collisions with H₂ and He. As a first step towards treating these reactions we are studying the interaction of AH with H. We have carried out variational calculations to determine an upper bound to the smallest internuclear distance at which the light particles are still bound to the nuclei. We are currently in the process of taking into account the motion of the nuclei. This will enable us to calculate cross-sections for low energy H-AH scattering. This revised version was published online in August 2006 with corrections to the Cover Date.     

Strong interactions at low energies

The lectures review some of the basic concepts relevant for an understanding of the low energy properties of the strong interactions: chiral symmetry, spontaneous symmetry breakdown, Goldstone bosons, quark condensate. The effective field theory used to analyze the low energy structure is briefly sketched. As an illustration, I discuss the implications of the recent data on the decay K→ππeν for the magnitude of the quark condensate.     

Future of neutrino experiments

Atmospheric, solar, reactor and accelerator neutrino oscillation experiments have measured Δm ₁₂², sin² θ ₁₂, |Δm ₂₃²| and sin² 2θ ₂₃. The next stage of the oscillation studies should be the observation of a finite sin² 2θ ₁₃. If a non-zero sin² 2θ ₁₃ is observed, the subsequent goals should be the observation of the CP violation and the determination sign of Δm ₂₃². Possible future neutrino oscillation experiments that could assess these questions are discussed.