Punzi-loss Abudinén, F.; Bertemes, M.; Bilokin, S. ...
The European physical journal. C, Particles and fields,
2022/2, Letnik:
82, Številka:
2
Journal Article
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Odprti dostop
We present the novel implementation of a non-differentiable metric approximation and a corresponding loss-scheduling aimed at the search for new particles of unknown mass in high energy physics ...experiments. We call the loss-scheduling, based on the minimisation of a figure-of-merit related function typical of particle physics, a Punzi-loss function, and the neural network that utilises this loss function a Punzi-net. We show that the Punzi-net outperforms standard multivariate analysis techniques and generalises well to mass hypotheses for which it was not trained. This is achieved by training a single classifier that provides a coherent and optimal classification of all signal hypotheses over the whole search space. Our result constitutes a complementary approach to fully differentiable analyses in particle physics. We implemented this work using PyTorch and provide users full access to a public repository containing all the codes and a training example.
Punzi-loss Abudinén, F; Bertemes, M; Bilokin, S ...
European physical journal. C, Particles and fields,
02/2022, Letnik:
82, Številka:
2
Journal Article
Recenzirano
Odprti dostop
We present the novel implementation of a non-differentiable metric approximation and a corresponding loss-scheduling aimed at the search for new particles of unknown mass in high energy physics ...experiments. We call the loss-scheduling, based on the minimisation of a figure-of-merit related function typical of particle physics, a Punzi-loss function, and the neural network that utilises this loss function a Punzi-net. We show that the Punzi-net outperforms standard multivariate analysis techniques and generalises well to mass hypotheses for which it was not trained. This is achieved by training a single classifier that provides a coherent and optimal classification of all signal hypotheses over the whole search space. Our result constitutes a complementary approach to fully differentiable analyses in particle physics. We implemented this work using PyTorch and provide users full access to a public repository containing all the codes and a training example.
We measure the branching fractions and CP asymmetries for the singly Cabibbo-suppressed decays $D^0 → π^+π^-η, D^0 → K^+K^-η$, and $D^0 → Φη$, using 980 fb-1 of data from the Belle experiment at the ...KEKB e+e- collider. We obtain $$\mathcal{B}(D^0 → π^+π^-η = \mathrm{1.22 ± 0.02 (stat) ± 0.02(syst) ± 0.03}(\mathcal{B}_{\mathrm{ref}}) \mathrm{x 10^{-3}}$$ $$\mathcal{B}(D^0 → K^+K^-η = \mathrm{1.80^{+0.07}_{-0.06}(stat) ± 0.04 (syst) ± 0.05}(\mathcal{B}_{\mathrm{ref}}) \mathrm{x 10^{-4}}$$ $$\mathcal{B}(D^0 → Φη = \mathrm{1.84 ± 0.09 (stat) ± 0.0 (syst) ± 0.05}(\mathcal{B}_{\mathrm{ref}}) \mathrm{x 10^{-4}}$$ where the third uncertainty ($\mathcal{B}_{\mathrm{ref}}$) is from the uncertainty in the branching fraction of the reference mode $D^0 → K^-π^+η$. The color-suppressed decay $D^0 → Φη$ is observed for the first time, with very high significance. The results for the CP asymmetries are $$A_{CP} (D^0 → π^+π^-η) = \mathrm{0.9 ± 1.2 (stat) ± 0.5 (syst)}\%$$ $$A_{CP} (D^0 → K^+K^-η) = \mathrm{-1.4 ± 3.3 (stat) ± 1.1 (syst)}\%$$ $$A_{CP} (D^0 → Φη) = \mathrm{-1.9 ± 4.4 (stat) ± 0.6 (syst)}\%$$ The results for $D^0 → π^+π^-η$ are a significant improvement over previous results. The branching fraction and ACP results for $D^0 → K^+K^-η$, and the ACP result for $D^0 → Φη$, are the first such measurements. No evidence for CP violation is found in any of these decays.
Reliable and well positioned human sources are essential for the US and its allies in an era of declining relations and rising tensions with China and Russia. The recruitment and handling of spies is ...essential if the US and its allies are to cool relations carefully, enact sound policy and curb the relentless intelligence operations of their adversaries. However, despite the superficially more open borders of China and Russia, technological advances have made the threat of street surveillance to the recruitment and handling of agents today as acute as it was in Cold War "denied area" states. This paper assesses the degree of street surveillance in contemporary Russia and China - including the impact of biometrics and online data history on the defensibility of cover and the severity of advanced CCTV networks - and the solutions intelligence agencies might adopt to address these problems. Despite the possibilities cyberspace offers espionage - for instance, by reducing the need for face to face meetings between intelligence officers and agents - the paper establishes the limitations of technological answers and argues that Western intelligence officers are entering a new era of Moscow and Beijing Rules in which they are more essential than ever and yet need to operate with absolute caution.
Compositional variations in the surfactants used to produce personal care products result in significant challenges during large scale manufacturing, for example errors in product viscosity. ...Characterisation of the surfactant can be completed using chromatographic techniques however these are time consuming and impractical during real-time manufacturing. Near infrared (NIR) absorption spectroscopy with a fibre-optic coupled transmission probe is proposed as an in-line method of determining the levels of unsulfated alcohol in sodium lauryl ether sulfate (SLES). NIR absorption spectra in the region of 4000 – 12000 cm−1 were collected for a range of supplier samples at three temperatures. Gas chromatography - mass spectrometry was used as a reference technique to quantify samples of SLES and quantitative chemometric data analysis was used to produce partial least squares (PLS) calibration models for the prediction of surfactant composition. PLS regression was performed on the data in the spectral regions between 7509 – 5334 cm−1 using a range of data pre-processing techniques to identify the best model. Models were evaluated using root mean square error of cross validation (RMSECV) and residual predictive deviation (RPD) as the primary indicator of model accuracy and robustness. A partial least squares regression model using a generalised least squares weighting data pre-processing approach was found to be the most robust in regards to sample non-homogeneity and temperature, producing a model with an RMSECV = 0.094 w/w% and RPD = 4.03. The model successfully predicted the unsulfated alcohol mass percentage in an external validation of unknown samples with alcohol levels within the model limits of 0.7–2.2 w/w%. Spectra acquired at a resolution of 8 cm−1 with 32 scans take just 16 seconds to obtain, proving that NIR spectroscopy can successfully be applied as an alternative analytical method to gas chromatography for the determination of low level impurities in viscous surfactant systems.
Gardner's syndrome is a variant of Familial Adenomatous Polyposis (FAP), a condition that manifests as hundreds of colorectal polyps likely to undergo malignant change by the fourth decade. Early ...diagnosis of this condition has the potential to be life saving for individuals and due to its inherited nature other family members can often also be affected. Additional features of Gardner's Syndrome include multiple jaw osteomas with missing teeth that can make prosthodontic treatment a challenge. This case report highlights the presenting features and the prosthodontic problems faced when treating a patient with Gardner's syndrome.
Abstract We present a search for the dark photon A′ in the B 0 → A′A′ decays, where A′ subsequently decays to e + e − , μ + μ − , and π + π − . The search is performed by analyzing 772 × 106 B B ¯ $$ ...B\overline{B} $$ events collected by the Belle detector at the KEKB e + e − energy-asymmetric collider at the ϒ(4S) resonance. No signal is found in the dark photon mass range 0.01 GeV/c 2 ≤ m A′ ≤ 2.62 GeV/c 2, and we set upper limits of the branching fraction of B 0 → A′A′ at the 90% confidence level. The products of branching fractions, ℬ B 0 → A ′ A ′ × ℬ A ′ → e + e − 2 $$ \mathrm{\mathcal{B}}\left({B}^0\to A^{\prime }A^{\prime}\right)\times \mathrm{\mathcal{B}}{\left(A\prime \to {e}^{+}{e}^{-}\right)}^2 $$ and ℬ B 0 → A ′ A ′ × ℬ A ′ → μ + μ − 2 $$ \mathrm{\mathcal{B}}\left({B}^0\to A^{\prime }A^{\prime}\right)\times \mathrm{\mathcal{B}}{\left(A\prime \to {\mu}^{+}{\mu}^{-}\right)}^2 $$ , have limits of the order of 10 −8 depending on the A′ mass. Furthermore, considering A′ decay rate to each pair of charged particles, the upper limits of ℬ B 0 → A ′ A ′ $$ \mathrm{\mathcal{B}}\left({B}^0\to A^{\prime }A^{\prime}\right) $$ are of the order of 10 −8–10 −5. From the upper limits of ℬ B 0 → A ′ A ′ $$ \mathrm{\mathcal{B}}\left({B}^0\to A^{\prime }A^{\prime}\right) $$ , we obtain the Higgs portal coupling for each assumed dark photon and dark Higgs mass. The Higgs portal couplings are of the order of 10 −2–10 −1 at m h ′ ≃ m B 0 $$ {m}_{h\prime}\simeq {m}_{B^0} $$ ± 40 MeV/c 2 and 10 −1–1 at m h ′ ≃ m B 0 $$ {m}_{h\prime}\simeq {m}_{B^0} $$ ± 3 GeV/c 2.
Abstract We present the first model-independent measurement of the CKM unitarity triangle angle ϕ 3 using B ± → D( K S 0 $$ {K}_{\mathrm{S}}^0 $$ π + π − π 0) K ± decays, where D indicates either a D ...0 or D ¯ $$ \overline{D} $$ 0 meson. Measurements of the strong-phase difference of the D → K S 0 $$ {K}_{\mathrm{S}}^0 $$ π + π − π 0 amplitude obtained from CLEO-c data are used as input. This analysis is based on the full Belle data set of 772 × 106 B B ¯ $$ \overline{B} $$ events collected at the Υ(4S) resonance. We obtain ϕ 3 = ( 5.7 − 8.8 + 10.2 $$ {5.7}_{-8.8}^{+10.2} $$ ±3.5±5.7) ° and the suppressed amplitude ratio r B = 0.323±0.147±0.023±0.051. Here the first uncertainty is statistical, the second is the experimental systematic, and the third is due to the precision of the strong-phase parameters measured from CLEO-c data. The 95% confidence interval on ϕ 3 is (−29.7, 109.5) ° , which is consistent with the current world average.
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