445 research outputs found
New Signature of low mass in decays
We explore a new approach to search for a low-mass particle
through decays by identifying its existence through parity-violating
phenomena in the isospin-violating final states of
and the corresponding charge conjugated states
of . Our investigation centers on a
generation-independent and leptophobic with its mass below 10 GeV.
Given the present experimental conditions at the Beijing Spectrometer
III~(BESIII) and the anticipated opportunities at the Super Tau Charm
Factory~(STCF), we conduct Monte-Carlo simulations to predict possible events
at both facilities. Our simulations indicate that BESIII experiments hold the
potential to detect signals in
if the polarization asymmetry paramter
attains a minimum threshold of 0.02. Notably, we foresee a
substantial enhancement in the precision of the lower limit estimation of
as well as a reduction in statistical uncertainty with
upcoming STCF experiments. Furthermore, it is essential to highlight that a
null result in the measurement of would impose stringent
constraints, requiring the coupling to be on the order of
.Comment: 9 pages, 3 figure
Isospin violating decays of vector charmonia
We study the isospin violating decays of vector charmonia to
and . They are dominated by
the single photon annihilation and can be evaluated reliably with timelike form
factors. We utilize the quark-pair creation model, which is valid for the OZI
suppressed decays, to evaluate the form factors. We obtain the branching
fractions of and
, which
are compatible with the measurements by the BESIII collaborations,
respectively. The decay asymmetries are found to be and
. We predict the branching fractions for mesonic final
states as and
, and the
corresponding decay asymmetries as and
, which can be examined at BESIII in the foreseeable
future.Comment: 14 pages, 3 figure
Efficient Non-Learning Similar Subtrajectory Search
Similar subtrajectory search is a finer-grained operator that can better
capture the similarities between one query trajectory and a portion of a data
trajectory than the traditional similar trajectory search, which requires the
two checked trajectories are similar to each other in whole. Many real
applications (e.g., trajectory clustering and trajectory join) utilize similar
subtrajectory search as a basic operator. It is considered that the time
complexity is O(mn^2) for exact algorithms to solve the similar subtrajectory
search problem under most trajectory distance functions in the existing
studies, where m is the length of the query trajectory and n is the length of
the data trajectory. In this paper, to the best of our knowledge, we are the
first to propose an exact algorithm to solve the similar subtrajectory search
problem in O(mn) time for most of widely used trajectory distance functions
(e.g., WED, DTW, ERP, EDR and Frechet distance). Through extensive experiments
on three real datasets, we demonstrate the efficiency and effectiveness of our
proposed algorithms.Comment: VLDB 202
Crop residue management and fertilization effects on soil organic matter and associated biological properties
Returning crop residue may result in nutrient reduction in soil in the first few years. A two-year field experiment was conducted to assess whether this negative effect is alleviated by improved crop residue management (CRM). Nine treatments (3 CRM and 3 N fertilizer rates) were used. The CRM treatments were (1) R0: 100 % of the N using mineral fertilizer with no crop residues return; (2) R: crop residue plus mineral fertilizer as for the R0; and (3) Rc: crop residue plus 83 % of the N using mineral and 17 % manure fertilizer. Each CRM received N fertilizer rates at 270, 360, and 450 kg N ha−1 year−1. At the end of the experiment, soil NO3-N was reduced by 33 % from the R relative to the R0 treatment, while the Rc treatment resulted in a 21 to 44 % increase in occluded particulate organic C and N, and 80 °C extracted dissolved organic N, 19 to 32 % increase in microbial biomass C and protease activity, and higher monounsaturated phospholipid fatty acid (PLFA):saturated PLFA ratio from stimulating growth of indigenous bacteria when compared with the R treatment. Principal component analysis showed that the Biolog and PLFA profiles in the three CRM treatments were different from each other. Overall, these properties were not influenced by the used N fertilizer rates. Our results indicated that application of 17 % of the total N using manure in a field with crop residues return was effective for improving potential plant N availability and labile soil organic matter, primarily due to a shift in the dominant microorganisms
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