Exotic ρ±ρ0\rho^\pm\rho^0 state photoproduction

It is shown that the list of unusual mesons planned for a careful study in photoproduction can be extended by the exotic states $X^\pm(1600)$ with $I^G(J ^{PC})=2^+(2^{++})$ which should be looked for in the $\rho^\pm\rho^0$ decay channels in the reactions $\gamma N\to\rho^\pm\rho^0N$ and $\gamma N\to\rho^\pm \rho^0\Delta$. The full classification of the $\rho^\pm\rho^0$ states by their quantum numbers is presented. A simple model for the spin structure of the $\gamma p\to f_2(1270)p$, $\gamma p\to a^0_2(1320)p$, and $\gamma N\to X^\pm (N, \Delta)$ reaction amplitudes is formulated and the tentative estimates of the corresponding cross sections at the incident photon energy $E_\gamma\approx 6$ GeV are obtained: $\sigma(\gamma p\to f_2(1270)p)\approx0.12$ $\mu$b, $\sigma(\gamma p\to a^0_2(1320)p)\approx0.25$ $\mu$b, $\sigma(\gamma N\to X^\pm N\to\rho^\pm\rho^0N)\approx0.018$ $\mu$b, and $\sigma(\gamma p\to X^-\Delta^{++ }\to\rho^-\rho^0\Delta^{++})\approx0.031$ $\mu$b. The problem of the $X^\pm$ signal extraction from the natural background due to the other $\pi^\pm\pi^0 \pi^+\pi^-$ production channels is discussed. In particular the estimates are presented for the $\gamma p\to h_1(1170)\pi^+n$, $\gamma p\to\rho'^{+}n\to \pi^+\pi^0\pi^+\pi^-n$, and $\gamma p\to\omega\rho^0p$ reaction cross sections. Our main conclusion is that the search for the exotic $X^\pm(2^+(2^{++}))$ states is quite feasible at JEFLAB facility. The expected yield of the $\gamma N\to X^\pm N\to\rho^\pm\rho^0N$ events in a 30-day run at the 100% detection efficiency approximates $2.8\times10^6$ events.Comment: 19 pages, revtex, 1 figure in postscipt, some comments and references added, a few minor typos corrected, to be published in Phys. Rev.

Effects of single and repeated prescribed burns on soil organic C and microbial activity in a Pinus halepensis plantation of Southern Italy

Wildfire has historically been a major disturbance in Mediterranean European ecosystems and prescribed burning is increasingly used here to mitigate possible damage and reduce hazard. This raises the issue of a possible negative impact on soil from repeated burning treatments. We investigated the effects of a single and repeated prescribed burning on total and extractable organic C, microbial biomass C, fungal mycelium, microbial activity, metabolic quotient and C mineralization rate in the fermentation layer (F-layer) and the 5-cm soil underneath of a Pinus halepensis Mill. plantation in the Cilento, Vallo di Diano e Alburni National Park, Southern Italy. Prescribed burning was sequentially applied in 2009 and 2014 and the measurements were performed during the first year following each burning treatment. The first treatment produced short-term effects on the microbial biomass and activity of the F-layer, whereas the soil layer underneath was virtually unaffected. Surprisingly, the second treatment had negligible effects on either layer, probably because of a reduction of the understory fuel load and changes in the stand structure after the first burning. Most remarkably, fire-induced changes in the soil parameters considered were generally smaller than over-time fluctuations

Soil microbial metabolism and organic carbon pool sas affected by prescribed burning in pine plantations of Southern Italy.

Prescribed burning is an important tool in forest management to reduce wildfire risk but it may produce alterations in organic C pool and microbial metabolism with consequences on C cycle and CO2 emission towards the atmosphere. This study aims at evaluating the effect of prescribed fire performed in Pinus pinaster and P. halepensis plantations of Cilento e Vallo di Diano National Park (Southern Italy) on total organic C, extractable organic C, microbial C, metabolic quotient (qCO2: mg CO2-C g-1 Cmic h-1) and rate of C mineralization (CMR: mg CO2-C g-1 Corg h-1) measured in the fermentation layer and in the soil beneath (0-5 cm depth) during the first 5 months after fire. No effect due to prescribed burning was found on total organic C neither in fermentation layer nor in soil beneath and only temporary increases in extractable organic C were found in fermentation layer of both plantation and in soil of P. pinaster plantation. However, some changes were caused by prescribed burning in the other parameters, mainly in fermentation layer, in particular, a reduction in microbial C and an increase in metabolic quotient, during the whole study period, and an increase in C mineralization rate in the first 5 h (P. pinaster plantation) or 11 d (P. halepensis plantation) since burn. Temporary increases in metabolic quotient and in C mineralization rate were also found in soil of P. pinaster plantation where a longer residence time of the flame occurred compared to that observed in the P. halepensis one. Data suggest that stress conditions produced by fire in fermentation layer caused a change in microbial activity towards a more dissipative metabolism (high qCO2), with a consequent possible increase in CO2 emission to the atmosphere. However, this possible increase should be counterbalanced by a decrease in CO2 emission due to the reduction in wildfire frequency and intensity that could occur if prescribed burning is used as a forest management tool

Asub1sub 1, Asub2sub 2, and Asub3sub 3 production in pipisup−sup -p YieldsYields pipisup−sup -pipisup−sup -pipisup+sup +p at 25 and 40 GeV/c

A sample of ~70,000 fitted events of the reaction pi /sup -/p yields pi /sup -/ i/sup -/ pi /sup +/p at 25 and 40 GeV/c was obtained with the CERN-WEP Boson Spectrometer at the Serpukhov Accelerator. A partial-wave analysis shows that: A/sub 1/ and A/sup 3/ cannot be described by a Breit--Wigner amplitude; the A/sub 2/ can be well described by a Breit--Wigner amplitude; although A/sup 1/, A/ sup 3/, and A/sup 2/ have different properties, the e nergy dependence of their production cross section is similar. (auth