118793954
Analysis of one hadron rich event
In this report arguments are presented to classify this hadron rich event as an interaction event and the consequences of this statement. For instance the total invariant mass would be estimated as ≈ 61 GeV/c2 and the pair of hadrons used for height estimation have invariant mass = 2.2 GeV/c2. Besides, tables showing the parametric and non-parametric analysis resulting in a criteria table and the resulting tables for the discrimination of γ or hadron induced showers were presented at the 16th ISVHECRI, held at Batavia, USA. The main point of hadron rich and Centauro events is the identification of the nature of the observed showers. The identification and energy determination of γ or hadron induced showers was made using 2 simulations. Complemented with the observation of photosensitive material under microscope it was determined that the event C16S086I037 could be classified as a hadron rich event. We used 10 reasonable scenarios for γ/hadron discrimination and obtained that the event is composed of 25 γ’s, 36 hadrons and 1 surviving and leading hadron. All these scenarios were reported at the 14th ISVHECRI, held in Weihai, China and resulted in rather constant values of physical quantities, like the mean transverse momentum of hadrons, < PTh >, and the mean inelasticity of γ-ray, < kγ >. Assuming that the most energetic shower is the surviving particle of an interaction and the tertiary produced particles are from normal multiple pion production, the characteristics of the interaction are: Energy of primary particle E0 = 1, 061 TeV, Inelasticity of collision K = 0.81, Mean inelasticity of γ-ray < kγ >= 0.27, Hadron induced showers energy/Total energy Qh = 0.90 ≈ Qh = 0.71, Rapidity density Nh/∆Y = (8.56 − 9.89), Mean energy of secondary hadrons < Eh >= (21.5 ± 4) TeV, Mean transverse momentum < PTh >= (1.2 ± 0.2) GeV/c, Upper bound of partial cross section σ ≤ (0.32 − 0.85)mb and life time τ ≤ 10−12 s.
120538058
Hadron rich and Centauro events
An exploratory statistical analysis of the event C16S086I037 was possible to do using two simulations. A γ and hadron induced showers recognition done on this event through a best fitting procedure shows identification of 25 and 37 for γ and hadron induced showers, respectively. Assuming that the most energetic shower is the surviving particle of an interaction and the tertiary produced particles are from normal multiple pion production, the characteristics of the interaction are: Energy of primary particle E 0 = 1 , 061  TeV , Inelasticity of collision K = 0.81 , Mean inelasticity of γ -ray k γ > = 0.27 , Hadron induced showers energy/Total energy Q h ′ = 0.90 ≈ Q h , Rapidity density N h / Δ Y = ( 8.56 – 9.89 ) , Mean energy of secondary hadrons E h > = ( 21.5 ± 4 )  TeV , Mean transverse momentum P T h > = ( 1.2 ± 0.2 )  GeV/c , Upper bound of partial cross section σ ⩽ ( 15 – 39 ) μ barn and life time τ ⩽ 10 −16  s . Without the surviving particle assumption, the values are: E 0 = 873  TeV , K = 1.0 , k γ > = 1 / 3 , Q h ′ = 0.90 , N h / Δ Y = ( 8.32 – 9.34 ) , E h > = ( 21 ± 3.5 )  TeV , P T h > = ( 1.0 ± 0.16 )  GeV/c . Using another simulation for energy determination with χ 2 > 3.16 for best fitting results 22 and 40 for γ and hadron induced showers, respectively. Under the surviving particle assumption, the figures are: Energy of primary particle E 0 = 1 , 047  TeV , Inelasticity of collision K = 0.80 , Mean inelasticity of γ -ray k γ > = 0.27 , Hadronic induced showers energy/Total energy Q h ′ = 0.89 ≈ Q h , Rapidity density N h / Δ Y = ( 10.25 − 13.19 ) , Mean energy of secondary hadrons E h > = ( 19 ± 3 )  TeV , Mean transverse momentum P T h > = ( 1.0 ± 0.2 )  GeV/c . That is, we get almost similar figures independently of simulation and a mean transverse momentum for this hadron-rich event similar to the Centauro events.
123642516
An EAS event observed in the early stage of development
Since 1969 the experiments of Brazil-Japan Collaboration showed the occurrence of a series of events, showing a region with a high concentration of electromagnetic particles, surrounded by isolated and/or groups of showers. These events were named “halo events” or “super-families”. Currently, we have more than a dozen of such events. The first of them, due to its aspect, was named “Andromeda”. We present here the main characteristics of a similar halo event, named C21S087I075. It has a halo region with many high energy showers in its border. Other small energy showers spread over the central and surrounding blocks (S088, S100, S101, I074). These isolated showers, classified as of hadronic or electromagnetic origin, present a fractional energy distribution compatible with that of a Centauro candidate event (C16S087I037), reported at this symposium [S.L.C. Barroso, P.C. Beggio, J.A. Chinellato, A.O. Carvalho, A. Mariano, R. Oliveira, E.H. Shibuya, in this issue of XIV ISVHECRI]. Moreover, the lateral distribution in the halo region is similar to that observed in other 3 halo events.
18592563
Competition between standard and exotic double beta decays
Abstract We discuss the contributions of higher order terms in weak Hamiltonian to the standard two-neutrino double beta decay. The formalism for the unique first forbidden transitions has been developed, and it is shown that they can alter the two-electron energy spectrum. Yet, their effect is too small to screen the detection of exotic neutrinoless double beta decays, which are candidates for testing the physics beyond the standard model.
7942120
Nuclear moments for the neutrinoless double beta decay II
The recently developed formalism for the evaluation of nuclear form factors in neutrinoless double beta decay is applied to $^{48}Ca$, $^{76}Ge$, $^{82}Se$, $^{100}Mo$, $^{128}Te$ and $^{130}Te$ nuclei. Explicit analytical expressions that follows from this theoretical development, in the single mode model for the decay of $^{48}Ca$, have been worked out. They are useful both for testing the full numerical calculations, and for analytically checking the consistency with other formalisms. Large configuration space calculations are compared with previous studies, where alternative formulations were used. Yet, besides using the G-matrix as residual interaction, we here use a simple $\delta$-force. Attention is paid to the connected effects of the short range nuclear correlations and the finite nucleon size. Constraints on lepton number violating terms in the weak Hamiltonian (effective neutrino Majorana mass and effective right-handed current coupling strengths) are deduced.