bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of roads on giant panda distribution: a mountain range scale evaluation
Authors: He Ke , Dai Qiang , Gu Xianghui , Zhang Zejun , Zhou Jiang , Qi Dunwu , Gu Xiaodong , Yang Xuyu , Zhang Wen , Yang Biao , Yang Zhisong
Published: February 2019

Few studies have focused on the mountain ranges scale effects of roads on wildlife. This lack of data could lead to an underestimation of the negative impact of roads on animal populations. We analyzed a dataset that included 74.4% of the giant panda population and covered 78.7% of the global giant panda habitat to estimate road-effect zones for major roads, and to investigate how these major roads influenced the distribution of giant pandas on a mountain range spatial scale. We found that the density of giant panda signs was significantly decreased by proximity to major roads. The effect zone reached 5,000 m from national roads and 1,500 m from provincial roads. Structural equation model analysis revealed that the strongest negative impact of major roads on giant pandas was via the reduction of nearby forest cover. The results should provide a better understanding of the impact of anthropogenic infrastructure and regional economic development on wildlife, thus providing a basis for conservation policy decisions. We suggest that the environmental impact assessment of proposed roadways or further researches on road ecological effects should expand to a larger scale and consider the possible habitat degradation caused by road access.
Aptamers as quality control tool for production, storage and biosimilarity of the anti-CD20 biopharmaceutical rituximab
Authors: Wildner Sabrina , Huber Sara , Regl Christof , Huber Christian G. , Lohrig Urs , Gadermaier Gabriele
Published: February 2019

Detailed analysis of biopharmaceuticals is crucial for safety, efficacy and stability. Aptamers, which are folded, single-stranded oligonucleotides, can be used as surrogate antibodies to detect subtle conformational changes. We aimed to generate and assess DNA aptamers against the therapeutic anti-CD20 antibody rituximab. Six rituximab-specific aptamers with Kd = 354–887 nM were obtained using the magnetic bead-based systematic evolution of ligands by exponential enrichment (SELEX) technology. Aptamer folds were analysed by online prediction tools and circular dichroism spectroscopy suggesting quadruplex structures for two aptamers while others present B-DNA helices. Aptamer binding and robustness with respect to minor differences in buffer composition or aptamer folding were verified in the enzyme-linked apta-sorbent assay. Five aptamers showed exclusive specificity to the Fab-fragment of rituximab while one aptamer revealed a broader recognition pattern to other monoclonal antibodies. Structural differences upon incubation at 40 °C for 72 h or UV exposure of rituximab were uncovered by four aptamers. High similarity between rituximab originator and biosimilar lots was demonstrated. The most sensitive aptamer (RA2) detected signal changes for all lots of a copy product suggesting conformational differences. For the first time, a panel of rituximab-specific aptamers was generated allowing the assessment of conformational coherence during production, storage, and biosimilarity of different products.
Understanding the phyto-interaction of heavy metal oxide bulk and nanoparticles: evaluation of seed germination, growth, bioaccumulation, and metallothionein production
Authors: Ahmed Bilal , Rizvi Asfa , Zaidi Almas , Khan Mohammad Saghir , Musarrat Javed
Published: February 2019

Phyto-interaction of heavy metal oxide nano and bulk particles with agriculturally important crops.
Constructing CsPbBrxI3−x nanocrystal/carbon nanotube composites with improved charge transfer and light harvesting for enhanced photoelectrochemical activity
Authors: Yang Mu-Zi , Xu Yang-Fan , Liao Jin-Feng , Wang Xu-Dong , Chen Hong-Yan , Kuang Dai-Bin
Published: February 2019

CsPbBr3I3−x/CNT hybrid thin-film photoelectrodes are fabricated and offer great potential in photoelectrochemical applications.
Coordination derived stable Ni–Co MOFs for foldable all-solid-state supercapacitors with high specific energy
Authors: Ye Changjing , Qin Qingqing , Liu Jiaqin , Mao Wenping , Yan Jian , Wang Yan , Cui Jiewu , Zhang Qi , Yang Liping , Wu Yucheng
Published: February 2019

Coordination derived stable Ni–Co MOF (833 F g−1) based foldable all-solid-state supercapacitors show a high specific energy of 77.7 W h kg−1.
Retraction: A highly concise and practical route to clavaminols, sphinganine and (+)-spisulosine via indium mediated allylation of α-hydrazino aldehyde and a theoretical insight into the stereochemical aspects of the reaction
Authors: Pandey Menaka , Chowdhury Partha Sarathi , Dutta Achintya Kumar , Kumar Pradeep , Pal Sourav
Published: February 2019

Retraction of ‘A highly concise and practical route to clavaminols, sphinganine and (+)-spisulosine via indium mediated allylation of α-hydrazino aldehyde and a theoretical insight into the stereochemical aspects of the reaction’ by Menaka Pandey et al., RSC Adv., 2013, 3, 15442–15448.
N+-ion irradiation engineering towards the efficient oxygen evolution reaction on NiO nanosheet arrays
Authors: Xia Baorui , Wang Tongtong , Jiang Xingdong , Li Jun , Zhang Tongming , Xi Pinxian , Gao Daqiang , Xue Desheng
Published: February 2019

The oxygen evolution reaction (OER) is an essential process in water splitting, which is highly relevant to the new generation of energy exploration approaches. N+ions irradiation is an effective method for improving the OER electrocatalytic capacity of NiO.
Simplest hyperchaotic system with only one piecewise linear term
Authors: Singh J.P. , Roy B.K.
Published: February 2019

The objective of this Letter is to report the development of the simplest hyperchaotic system in comparison with all existing simplest hyperchaotic systems. The proposed system does not contain any non‐linear (product, quadratic or cubic) term and has a total of eight terms including the only one piecewise linear term. The circuit of the proposed simplest hyperchaotic system is implemented in hardware with fewer components and without using a multiplier. To the best of the authors’ knowledge, such simplest hyperchaotic system is not reported in the literature.
Offset‐cancelling current‐mode sense amplifier for fast‐read eFlash memory
Authors: Zhu Wenyi , Jiang Jianwei , Zhang Haineng , Xiao Jun , Yang Guangjun , Zou Shichang
Published: February 2019

A novel offset‐cancelling current‐mode sense amplifier (OC‐CSA) to improve the sensing speed of embedded flash (eFlash) memory is proposed. To reduce the precharge time related to random address transitions, this OC‐CSA adopts a new precharge acceleration scheme. Moreover, by employing offset cancellation, double sensing margin and strong positive feedback techniques, the new OC‐CSA can achieve a sensing speed 1.6 × faster than other OC‐CSAs. A 130 nm 1 Mb eFlash macro to confirm the high‐speed capability of the proposed OC‐CSA is fabricated. The experiment results show the new OC‐CSA can achieve a read access time of 11 ns at VDD = 1.3 V.
Genetic algorithm‐based cellular network optimisation considering positioning applications
Authors: Campos Rafael Saraiva , Lovisolo Lisandro
Published: February 2019

This work examines the use of genetic algorithms (GAs) to optimise two different problems regarding positioning applications in wireless communication systems. The first problem involves speeding‐up the search for the mobile station (MS) position in cellular networks, when using a database correlation (DCM) technique. While addressing this problem, this work investigates three different approaches for using GA (DcmGaFull, DcmGaBs and DcmGaBS+RTT) and evaluates their performances (in terms of computational complexity and positioning precision) in two different regions. The performance of those methods was compared with those of the standard fall‐back methods for emergency call locating in 2G, 3G and 4G networks: cell identity (CID) and enhanced CID (ECID). Method DcmGaBs+RTT, originally proposed in this work, achieved the best performance, both in terms of lower latency and higher precision, in the two test areas. The second problem concerned optimising the deployment of a new BTS in two different test regions, while considering parameters such as coverage, traffic density and CID and ECID positioning error. This was done considering also the mixed objective of weighting the positioning error by the traffic demand, as a higher number of emergency calls are expected to be generated from areas with higher traffic density.
Energy efficient network localisation using hybrid TOA/AOA measurements
Authors: Yuan Peng , Zhang Tingting , Yang Nian , Xu Hongguang , Zhang Qinyu
Published: February 2019

Accurate position information is the basis of many modern wireless applications. Hybrid time of arrival/angle of arrival (TOA/AOA) measurements are attractive in location‐aware networks, especially when the number of anchors is limited. Recent investigations show that proper resource allocation is of great importance in cost and complexity restricted localisation networks. In this study, the authors focus on the energy efficient localisation strategy using hybrid TOA/AOA measurements. A joint resource allocation and antenna selection framework is presented to minimise the localisation error. Due to the essential non‐convexity of the original formulated integer programming problem, a low complexity and high accuracy two‐phase solution is presented to perform proper convex relaxations. Numeric results validate the authors' analysis, and provide meaningful insights to practical TOA/AOA localisation networks.
On the average of the product of two Gaussian Q functions over η − μ and κ − μ fading channels using MRC diversity reception
Authors: Sadhwani Dharmendra , Yadav Ram Narayan
Published: February 2019

In this study, the authors propose a simple and tighter approximation to an integral representing the average of the product of two Gaussian Q functions over parametric and fading channels. This facilitates the symbol error probability computation of most of the coherent digital modulation techniques over and fading distributions. In order to improve the error performance of these digital modulation schemes, maximal‐ratio combining (MRC) diversity reception is also employed. Moreover, since and are generic fading scenarios, the widely used popular fading models like Rayleigh, one‐sided Gaussian, Nakagami‐m, Nakagami‐q and Rician can be unified under one umbrella. This study also gives an insight of the asymptotic approximations of the proposed integrals. In addition, the analytical framework is validated with the help of Monte Carlo simulations, which enables an easy practical implementation of the proposed work.
Transient and steady‐state modelling of healthy and eccentric induction motors considering the main and third harmonic saturation factors
Authors: Ghoggal Adel , Hamida Amel Hadri
Published: February 2019

This paper deals with the modelling of magnetic saturation in induction motors (IMs) with particular focus on the equivalent or fictitious air‐gap permeance technique. Besides, an improved version of this technique is provided so as to account for the transient starting process and the third harmonic saturation factor in addition to the fundamental one. This is for the symmetric case. Under air‐gap eccentricities, extension of both saturation models is proposed using the varying saturation factor solution. The 2D‐modified winding function approach (2D‐MWFA) is the base of the inductance calculation and the state equations are derived from the well‐known multiple coupled circuit model (MCCM). Thanks to such considerations, skew effect, rise of the magneto‐motive force (MMF) across the slots, all winding harmonics, and many faulty states can be judiciously taken into account. In summary, five derived saturation models are discussed in favour of a good handling of the saturation phenomenon in cage IMs. The work is supported by extensive simulation and experimental results of eccentricity, broken rotor bar, and combined faults.
Design and analysis of a virtual synchronous generator control strategy in microgrid application for stand‐alone sites
Authors: El Tawil Tony , Yao Gang , Charpentier Jean Frédéric , Benbouzid Mohamed
Published: February 2019

This paper deals with the design and analysis of a virtual synchronous generator (VSG) control strategy applied to a renewable‐based system devoted to energy production in a stand‐alone microgrid context. The studied hybrid energy production system consists of renewable‐based energy production systems, a diesel power plant (DPP), and an energy storage system (ESS). The first part of the study will deal with the design of a single renewable energy source controlled using the VSG control strategy. In the second part, multiple renewable energy sources, similar to the one presented in the first part, will be connected in parallel to form a renewable farm. Finally, in a third part, the studied renewable farm will be integrated in a full hybrid system. In each part of the proposed study, the system power output will be evaluated and the voltage and frequency variations will be carefully analysed.
Efficient period elimination Benders decomposition for network‐constrained AC unit commitment
Authors: Ghanbari‐Firouzabadi Ali , Pirayesh Abolfazl , Esmaili Masoud
Published: February 2019

Recent complexities in interconnected power system operation call for more efficient and fast approaches for operational problems including network‐constrained unit commitment (NCUC). In this study, an algorithm called period‐elimination Benders decomposition (PEBD) is proposed to enhance the computational efficiency of AC NCUC problems. After linearising the AC NCUC, two subproblems (SPs) are defined to ensure power balance at buses as well as constraints of branches and inter‐regional transactions. In the classical Benders decomposition (BD), all time periods are solved at all iterations up to convergence. However, in the proposed PEBD, a time period that satisfies a SP in an iteration is eliminated from the solution procedure of that SP at next iterations. After both SPs are satisfied for all time periods, the solution is checked for interrelation constraints and a few more iterations may be needed to finalise the solution. The efficiency and accuracy of the proposed PEBD method are verified by examining it on two test systems. It is found that the PEBD greatly enhances the speed of NCUC, especially in larger power systems due to eliminating unnecessary calculations for satisfied time periods.
Modelling virtual oscillator‐controlled microgrids
Authors: Shi Zhan , Li Jiacheng , Callegaro Leonardo , Nurdin Hendra I. , Fletcher John E.
Published: February 2019

Virtual oscillator control (VOC) is an emerging non‐linear technique to control the terminal voltage of inverters in ac micro‐grids. This study compares two small‐signal models of VOC, obtained from average VOC dynamics over one ac cycle. The first model from previous literature is based on the approximation of real and reactive power in the average dynamics by the corresponding instantaneous values of power. The second model proposed in this study, in contrast to the first, approximates the average power by filtered power from a second‐order low‐pass filter. The two models are evaluated by eigenvalue and participation analyses. Simulations and experimental results are used to verify the models, by observing transient responses of a three‐phase inverter subject to a step change in the load. The proposed linearised model can tracks transients of the output voltage and current more accurately than the existing technique both in the simulations and experimental tests. The proposed linearised VOC model enables a more precise small‐signal stability and transient analysis of the average VOC dynamics. In conclusion, this improvement benefits stability studies when system parameters are changed or load disturbances are added to virtual oscillator‐controlled inverter‐based micro‐grids.
Decentralised resilient autonomous control architecture for dynamic microgrids
Authors: Bani‐Ahmed Abedalsalam , Rashidi Mohammed , Nasiri Adel
Published: February 2019

Microgrids serve as an integral part of future power distribution systems. Typically, microgrids are managed by centralised controllers. There are two major concerns about using a single centralised controller. The controller can become a performance and reliability bottleneck for the entire system, where its failure can bring the entire system down. Excessive communication delays can also degrade the system performance. As a solution, a true decentralised control architecture for microgrids is proposed, designed, developed, and tested here. Distributing the controls to local agents decreases the possibility of network congestion to occur. Decentralisation will also enhance the reliability of the system since the single point of failure is replaced by a distributed architecture. The proof‐of‐concept of true decentralisation of microgrid control architecture is implemented using Hardware‐in‐the‐Loop Platform. Device level and system level controller and interaction models are defined for a self‐coordination. Also, microgrid energy management system (EMS) and control case scenarios are demonstrated. The experimental results show the robustness of the proposed architecture.
Adaptive optimal waveform design algorithm based on frequency‐stepped chirp signal
Authors: Fu Wei , Jiang Defu , Gao Yiyue , Li Na
Published: February 2019

In this study, the authors propose an adaptive optimal waveform design algorithm, based on a frequency‐stepped chirp signal with arbitrary sub‐pulse bandwidths and chirp slopes. The waveform is designed to maximise the signal‐to‐interference‐plus‐noise ratio at the receiver. The integral sidelobe level of an autocorrelation function is constrained at a low level, thereby increasing the detection probability of the weak echoes reflected from dim targets. An energy constraint and a low peak‐to‐average power ratio constraint are also taken into account owing to the flexible power allocation for interference suppression. By doing so, the radar system improves the efficiency of the transmitter power resources and avoids the non‐linear effects of the power amplifier. What is more, a cyclic iterative algorithm is employed to solve the optimisation problem. At last, numerical simulation results evaluate the effectiveness of the designed waveform compared with a linear frequency modulation signal, resulting in a great improvement in the target detection performance.
Analysis and test of a wireless impedance‐loaded SAW sensor
Authors: Zhu Xifeng , Xing Jianchun , Xie Liqiang , Wang Tianxian
Published: February 2019

Instead of a conventional wireless transceiver system that requires batteries and complex circuits, the surface acoustic wave (SAW) sensor enables wireless passive measurement. A sensor consisting of an SAW device and external impedance sensing element is analysed. Since the reflection coefficient of the reflective grating on the SAW device depends on the load impedance, the echo characteristics are influenced by the change in the impedance of external sensing element. A resistance sensor or a capacitive sensor is selected as the external sensing element. The two different types of sensors are simulated using coupling‐of‐mode (COM) modelling, and the relationships between amplitude and phase with load impedance are analysed. On the basis of COM theory, a wireless impedance‐loaded SAW sensor is fabricated by the lift‐off process and tested by a network analyser to verify the simulation results. It is observed that the test results agree well with the simulation results. The phase change is more sensitive than the amplitude based on the results obtained. The sensitivity is 0.274°/Ω for the sensor with resistance and the sensitivity of the sensor with capacitance is 1.096°/pF. These results can guide the design of the high sensitivity impedance‐loaded SAW sensors in the future.
Operational experience and modelling of biomass combustion process in cogeneration systems with ORC units
Authors: Kalina Jacek , Sachajdak Andrzej , Strzałka Rafał , Świerzewski Mateusz , Ćwięka Jerzy
Published: February 2019

Organic Rankine Cycle (ORC) technology is nowadays considered as interesting option for utilization of local biomass resources. The number of plants worldwide is constantly growing within typical range of electric power output form 0.2 to 3.0 MW. In such systems biomass combustion chambers with step or vibrating grates are used. Heat is transferred to the thermal oil in a separate spiral heat exchanger. The biggest problems in such system are variable and inaccurately predictable properties of biomass that directly influences operation of combustion equipment, and thus the performance of entire cogeneration plant. In this paper experiences from two plants are presented. The plants are located in Krosno (Poland) and in Ostfildern near Stuttgart, Germany. In the first one high quality wood chips are used whereas the second one is powered by low quality biomass with the mass ash content approaching 18%. Although similar, both plants use different strategies to control the combustion process. Long term measurements are used to develop biomass combustion models in the plants. The paper also presents results of implementation of the online optic measurement system for monitoring of biomass properties such as LHV, ash and water content.
Studies on the effectiveness of SCR catalysts during combustion of pulverized coal
Authors: Pronobis Marek , Kalisz Sylwester , Mroczek Kazimierz , Walewski Andrzej , Wejkowski Robert , Wojnar Wacław , Gądek Waldemar , Kress Tomasz , Tymoszuk Mateusz , Maj Izabella
Published: February 2019

The motivation of this paper is new NOx emission regulations according to IED Directive 2010/75/EU of EU which introduce the BAT’s conclusions as binding. The paper presents the methodology and results of research on the effectiveness of SCR catalysts during combustion of pulverised coal in a model furnace installed at the Institute of Power Engineering and Turbomachinery of the Silesian University of Technology (IPET). The aim of the research was to search for catalysts that could be placed in a regenerative rotary air heater - RAH-SCR. Two catalysts were tested: a commercial plate-type based on V2O5 and a prototype ceramic based on platinum. Presented results of investigation demonstrate a potentially high efficiency of RAH-SCR installations which can meet new environmental regulations of NOx emission. The highest NOx reduction efficiency (92.87%) was obtained for an industrial catalyst at 329°C, from about 436.3 to 31.1 mg/m3 as NO2 @ 6%O2 to 31,1. At lower temperature, 260°C maximum efficiency of NOx reduction does not exceed 60%, from 440,0 to 169,6 mg/m3. The placement of the catalyst in the RAH can also be a support for SNCR installations due to the increase in DeNOx efficiency and reduction of NH3 slip.
An analysis of power losses in nanocrystalline and thin-gauge non-oriented SiFe materials for application to high-speed electrical machines
Authors: Vo Anh-Tuan , Fassenet Marylin , Arbenz Laure , Kedous-Lebouc Afef , Espanet Christophe
Published: February 2019

In this paper, the potential of thin sheet SiFe NO20 and nanocrystalline materials for the realization of the magnetic circuit of high-speed machines is analyzed in a complete procedure. Firstly, intrinsic properties of materials are precisely characterized. Next, the original and a modified model of Bertotti are applied for the modeling of power losses. These models are then used to predict losses in a simplified test bench which simulates the magnetic core of a real machine. FEM simulations in Altair FLUX 2D and experimental measurements are respectively carried out and results obtained show a good agreement leading to the confirmation of the potential of materials and the validation of the realized procedure.
Time-Like Baryon Transitions studies with HADES
Authors: Ramstein B. , Adamczewski-Musch J. , Arnold O. , Arnoldi-Meadows B. , Belounnas A. , Belyaev A. , Biernat J. , Blanco A. , Blume C. , Böhmer M. , Bordalo P. , Chlad L. , Chudoba P. , Ciepał I. , Deveaux C. , Dittert D. , Dreyer J. , Fabbietti L. , Fateev O. , Fonte P. , Franco C. , Friese J. , Fröhlich I. , Galatyuk T. , Garzón J. A. , Gernhäuser R. , Gillitzer A. , Golubeva M. , Greifenhagen R. , Guber F. , Gumberidze M. , Harabasz S. , Heinz T. , Hennino T. , Himmelreich M. , Höhne C. , Holzmann R. , Ierusalimov A. , Ivanov V. , Ivashkin A. , Kämpfer B. , Kajetanowicz M. , Kampert K-H. , Karavicheva T. , Kardan B. , Khomyakov V. , Koenig I. , Koenig W. , Korcyl G. , Kornakov G. , Kornas F. , Kotte R. , Kozela A. , Kuboś J. , Kugler A. , Kunz T. , Kurepin A. , Kurilkin P. , Kushpil V , Ladygin V. , Lalik R. , Lebedev A. , Linev S. , Liu M. , Lopes L. , Lorenz M. , Lykasov G. , Mahmoud T. , Malakhov A. , Markert J. , Maurus S. , Metag V. , Michel J. , Mihaylov D.M. , Mikhaylov V. , Morozov S. , Müntz C. , Naumann L. , Nowakowski K. , Parpottas Y. , Patel V. , Pauly C. , Pechenov V. , Pechenova O. , Pereira A. , Petousis V. , Petukhov O. , Pfeifer D. , Pietraszko J. , Przygoda W. , Pysz K. , Ramos S. , Reshetin A. , Ritman L. , Rodriguez-Ramos P. , Rost A. , Sadovsky A. , Salabura P. , Scheib T. , Schuldes H. , Schwab E. , Scozzi F. , Seck F. , Sellheim P. , Selyuzhenkov I. , Silva L. , Smyrski J. , Sobiella M. , Spataro S. , Spies S. , Ströbele H. , Stroth J. , Strzempek P. , Svoboda O. , Szala M. , Taranenko A. , Tlusty P. , Traxler M. , Troyan A. , Tsertos H. , Wagner V. , Wendisch C. , Wiebusch M.G. , Wintz P. , Wirth J. , Włoch B. , Zhilin A. , Zinchenko A. , Zumbruch P. , Zuschke M.
Published: February 2019

The HADES collaboration uses the e+e−production as a probe of the resonance matter produced in collisions at incident energies of 1-3.5 GeV/nucleon at GSI. Elementary reactions provide useful references for these studies and give information on resonance Dalitz decays (R→Ne+e−). Such processes are sensitive to the structure of time-like electromagnetic baryon transitions in a kinematic range where (off-shell) vector mesons play a crucial role. Results obtained in proton-proton reactions and in a commissioning pion-beam experiment are reported and prospects for future pion beam experiments and for first hyperon Dalitz decay measurements are described. The connection with the investigations of medium effects to be continued with HADES in the next years at SIS18 and SIS100 is also discussed.
Heavy mesons in the Quark Model
Authors: Entem D.R. , Ortega P.G. , Segovia J. , Fernández F.
Published: February 2019

Since the discovery of theJ/ψ, the quark model was very successful in describing the spectrum and properties of heavy mesons including only q̄ components. However since 2003, with the discovery of theX(3872), many states that can not be accommodated on the naive quark model have been discovered, and they made unavoidable to include higher Fock components on the heavy meson states. We will give an overview of the success of the quark model for heavy mesons and point some of the states that are likely to be more complicated structures such as meson-meson molecules.
Search for the η-mesic bound states with the WASA-at-COSY detector
Authors: Skurzok Magdalena
Published: February 2019

The experiments dedicated to the search for η-mesic Helium were performed with high statistics using WASA detection setups installed at the COSY accelerator in the Research Center Juelich. The search for the η-mesic bound states is conducted via the measurement of the excitation function for selected decay channels of the He-η systems using unique ramped beam technique. This report presents recent status of the data analysis.
Eta and Etaprime Photoproduction on the Nucleon with the Isobar Model EtaMAID2018
Authors: Tiator L. , Gorchtein M. , Kashevarov V. , Nikonov K. , Ostrick M. , Hadžimehmedović M. , Omerović R. , Osmanović H. , Stahov J. , Švarc A.
Published: February 2019

The isobar model EtaMAID has been updated with new and high precision data for η and η′ photoproduction on protons and neutrons from MAMI, ELSA, GRAAL and CLAS. The background is described in a recently developed Regge-cut model, and for the resonance part the whole list of nucleon resonances has been investigated with 21 N* states contributing to η photoproduction and 12 N* states contributing to η′ photoproduction. Finally, the possibility of a narrow resonance near W = 1900 MeV is discussed, that would be able to explain unexpected energy and angular dependence of observables in p(γ, η′)p near η threshold.
Unitarity, analyticity and duality constraints in η and π photoproduction
Authors: Gorchtein Mikhail
Published: February 2019

We report an update of the isobar model EtaMAID. A new approach is proposed to avoid double counting in the overlap region of Regge and resonances. Dispersion relation is applied on top of the isobar model, and both models describe the data equally well. Application of these ideas to pion photoproduction is discussed.
The pole structure of low energy πN scattering amplitudes
Authors: Wang Yu-Fei
Published: February 2019

This report presents an investigation of the pion-nucleon elastic scattering in low energy region using a production representation of the partial wave S matrix. The phase shifts are separated into contributions from poles and branch cuts, where the left-hand cut term can be evaluated by tree-level covariant baryon chiral perturbation theory. A comparison between the sum of known contributions and the data in S- and P- wave channels is made. It is found that the known components in S11 and P11 channels are far from enough to saturate the corresponding experimental data, indicating the existence of low-lying hidden poles. The positions of those hidden poles are figured out and the physics behind them are explored.
Measurement of helicity dependence of single π0 photoproduction on deuteron
Authors: Cividini Federico
Published: February 2019

The study of the properties of the baryon resonances gives essential constraints on models for nucleon structure. Pion-photoproduction is a powerful tool to excite the nucleon to an intermediate resonant state and, in combination with polarised beams/targets, plays an important role in the investigation of the nucleon resonances. Data for polarisation observables accessible using a polarised photon beam and/or polarised nucleon targets are scarce in many channels, especially in those involving a neutron target. A systematic measurement is performed at the Mainz facility by the A2@MAMI collaboration. This talk will focus on the experiment performed at the Mainz Microtron, using a circularly polarised photon beam and a longitudinally polarised deuteron target, in conjunction with the large acceptance Crystal Ball/TAPS detection setup. An overview of the status of the experiment will be given, together with the preliminary results of polarised cross section from deuteron and of the double polarization observable E for the single π0 photoproduction reaction from the quasi-free proton and quasi-free neutron.
Dielectron pairs from η meson decays at WASA detector
Authors: Pszczel D. , Stepaniak J.
Published: February 2019

We present the results of the analysis of η → e+e−γ and η → e+e− decays. The experimental data were collected in proton-proton collisions at incident proton kinetic energy 1.4 GeV using the WASA detector and the COSY storage ring. We describe the extraction procedure of the η meson transition form factor, based on a sample of around 108 η mesons, and show an attempt to search for physics beyond the Standard Model that led to the setting of an upper limit on the coupling between photons and hypothetical dark bosons. We also provide an estimate of the branching ratio upper limit for the very rare η → e+e− decay.
A revision of radiative corrections to double-Dalitz decays
Authors: Sanchez-Puertas Pablo , Kampf K. , Novotný J.
Published: February 2019

The radiative corrections to double-Dalitz $({P\rightarrow\overline ll\overline l'l'})$ decays are revisited and completed up to next-to-leading order in QED, finding mild differences with respect to previous studies. These might be relevant for extracting information about the mesons transition form factors, which play an important role in determining the hadronic light-by-light contribution to the anomalous magnetic moment of the muon.
On the width of the Δ(1232) in NΔ and ΔΔ states
Authors: Niskanen Jouni A.
Published: February 2019

Due to the finite kinetic energy in the intermediate NΔ state the (internal) energy available for mesonic decay is decreased and consequently the effective NΔ width is suppressed in NN scattering. The same can happen also in ΔΔ case. Also the NΔ angular momentum suppresses the width as well, while the effect of the initial NN angular momentum is more subtle. The state dependence affects e.g. pion production observables and can also be seen as the origin of T = 1 “dibaryons”.
Light hadron spectroscopy at BESIII
Authors: Xiong Xian
Published: February 2019

Light hadron spectroscopy is one of the most important physics goals of high statistics of charmonium decays collected at BESIII which provide an excellent place for hunting gluonic excitations and studying strangeonium. In this proceeding, we will introduce two analyses for gluonic states study on η(1405)/η(1475) puzzle, X(1835) and exotic states and two analyses for strangeonium(like) states study on Y(2175) and Zs state.
The most correct ρ0(770) meson mass and width values
Authors: Bartoš Erik , Dubnička Stanislav , Dubničková Anna Z. , Kamiński Robert , Liptaj Andrej
Published: February 2019

By application of the pion electromagnetic form factor and also the P-wave isovector ππ scattering phase shift parametrizations, following from the first principles, like unitarity and analyticity, for a description of the corresponding accurate data, it is clearly demonstrated that the ρ0(770) meson mass and width values obtained by the Gounaris-Sakurai model in a description of the same data can not be accepted as correct ones.
Spectroscopy of kaonic atoms at DAFNE and J-PARC
Authors: Marton J. , Amirkhan A. , Baniahmad A. , Bazzi M. , Bellotti G. , Berucci C. , Bosnar D. , Bragadireanu M. , Cargnelli M. , Curceanu C. , Dawood Butt A. , Del Grande R. , Fabbietti L. , Fiorini C. , Ghio F. , Guaraldo C. , Iliescu M. , Iwasaki M. , Levi Sandri P. , Miliucci M. , Moskal P. , Niedźwiecki S. , Okada S. , Pietreanu D. , Piscicchia K. , Shi H. , Silarski M. , Sirghi D. , Sirghi F. , Skurzok M. , Spallone A. , Tatsuno H. , Vazquez Doce O. , Widmann E. , Zmeskal J.
Published: February 2019

The interaction of antikaons (K−) with nucleons and nuclei in the low-energy regime represents a very active research field in hadron physics. A unique and rather direct experimental access to the antikaon-nucleon scattering lengths is provided by precision X-ray spectroscopy of transitions in low-lying states in the lightest kaonic atoms (i.e. kaonic hydrogen and deuterium). In the SIDDHARTA experiment at the electron-positron collider DAFNE of LNFINFN we measured the most precise values of the strong interaction observables in conic hydrogen. The strong interaction on the 1s ground state of the electromagnetically bound K-p atom causes an energy shift and broadening of the 1s state. SIDDHARTA will extend the spectroscopy to kaonic deuterium to get access to the antikaon-neutron interaction and thus the isospin dependent scattering lengths. At J-PARC a kaon beam is used in a complementary experiment with a different setup for spectroscopy of kaonic deuterium atoms. The talk will give an overview of the of the upcoming experiments SIDDHARTA and the complementary experiment at J-PARC.Furthermore, the implications of the experiments for the theory of low-energy strong interaction with strangeness will be discussed.
Central exclusive production of K+K− pairs in proton-proton collisions
Authors: Lebiedowicz Piotr , Szczurek Antoni , Nachtmann Otto
Published: February 2019

We discuss central exclusive diffractive production of light mesons in the reactions $pp \to pp{\pi ^ + }{\pi ^ - }$ and $pp \to pp{K^ + }{K^ - }$. The calculation is based on a tensor-pomeron approach. We include a purely diffractive dipion continuum, and the scalar f0(980), f0(1500), f0(1710) and tensor f2(1770), ${f^{\prime}_2}(1525)$ resonances decaying into pseudoscalar meson pairs. We include also photoproduction mechanisms for the nonresonant (Drell-Söding) and the ϕ(1020) resonance contributions. The theoretical results are compared with existing CDF experimental data and predictions for being carried out LHC experiments are presented. The distributions in dimeson invariant mass and in a special "glueball filter variable" including the interference effects of resonance and dimeson continuum are presented.
Hot medium effects on pseudotensor K2(1820) meson
Authors: Türkan A. , Dağ H. , Süngü J.Y. , Veli Veliev E.
Published: February 2019

The investigation of mesons in hot medium can give valuable information about the nature of QCD vacuum and deconfinement phase transitions. In this study, thermal properties of pseudotensor K2(1820) meson is examined via QCD sum rules at finite temperature. The mass and the decay constant of K2(1820) are estimated up to dimension-five by considering the new operators emerging at finite temperature. It is seen that after a certain temperature, the decay constant and the mass decrease significantly due to the hot medium effects.
Λp correlated production from low energy K−12C interactions by AMADEUS
Authors: Del Grande R. , Bazzi M. , Belloti G. , Bragadireanu A. M. , Bosnar D. , Butt A. D. , Cargnelli M. , Curceanu C. , De Paolis L. , Fabbietti L. , Fiorini C. , Ghio F. , Guaraldo C. , Hayano R. S. , Iliescu M. , Iwasaki M. , Levi Sandri P. , Marton J. , Miliucci M. , Moskal P. , Okada S. , Pietreanu D. , Piscicchia K. , Ramos A. , Scordo A. , Shi H. , Silarski M. , Sirghi D. L. , Sirghi F. , Skurzok M. , Spallone A. , Vazquez Doce O. , Widmann E. , Wycech S. , Zmeskal J.
Published: February 2019

The main steps for the analysis of the Λp correlated production in low-energy K− captures on Carbon nuclei, performed by the AMADEUS collaboration, are presented. The goal is to perform the first comprehensive study of the K− absorption on two, three and four nucleons, exploiting the lowmomentum K−s (pK ~ 127 MeV/c) produced at the DAΦNE collider, and to measure the low-energy cross sections and branching ratios of the K− multinucleon absorption processes in both the Λp and Σ0p channels. An integrated luminosity of 1.74 fb−1 collected during the KLOE 2004/2005 data campaign is analysed by reconstructing the Λp final state.
Feasibility studies of production and electromagnetic decay studies of hyperons for HADES
Authors: Nowakowski Krzysztof , Kuboś Joanna
Published: February 2019

The spectrum of excited states of single and double strange hyperons is only poorly known. Their internal structure is controversially discussed within quark, bag and molecular models. The most famous example is Λ(1405). In this context radiative decays are predicted to be an ideal tool to discriminate between various predictions. Moreover, Ξ−production yield measured by HADES in Ar+KCl@1.76 GeV andp+Nb@3.5 GeV experiments strongly overshoots theory predictions and calls for more detailed studies in elementary collisions. In our poster we show results of the feasibility studies for the HADES detector of the cascade production close to the threshold and also the radiative decays of the excited hyperon states. Three bench mark channels: $pp \to \Lambda (15020){K^ + }p \to \Lambda {e^ + }{e^ - }{K^ + }p$, $pp \to \Lambda (1405){K^ + }p \to \Lambda {e^ + }{e^ - }{K^ + }p$ and $pp \to \Sigma (1385){K^ + }p \to \Lambda {e^ + }{e^ - }{K^ + }p$, at beam energyEk= 4.5 GeV have been put into extensive simulation studies together with the most significant background channels. We will show the results including expected count rates and signal to background ratios.
The Y(4260) and Y(4360) enhancements within coupled-channels
Authors: Coito Susana
Published: February 2019

Puzzling structures have been observed in the charmonium energy region, namely the Y(4260) and the Y(4360), that cannot be easily accommodated within quark model frameworks. The proximity of nearby dominant hadronic thresholds suggests that they play an important role in the formation of the enhancements. We present results of an unitarized effective Lagrangian model, where mesonic loops, equivalent to coupled-channels, and charmonium vectors ψ interplay to generate line-shapes and poles.
Production asymmetry of open charm mesons within unfavoured ragmentation scenario
Authors: Maciuła Rafał
Published: February 2019

We consider unfavoured light quark/antiquark to D meson fragmentation. We discuss nonperturbative effects for small transverse momenta. The asymmetry for D+ and D- production measured by the LHCb collaboration provides natural constraints on the parton (quark/antiquark) fragmentation functions. We find that already a fraction of $q/\overline q \to D$ fragmentation probability is sufficient to account for the measured asymmetry. Large D-meson production asymmetries are found for large xF which is related to dominance of light quark/antiquark $q/\overline q \to D$ fragmentation over the standard c → D fragmentation. As a consequence, prompt atmospheric neutrino flux at high neutrino energies can be much larger than for the conventional c → D fragmentation. The latter can constitute a sizeable background for the cosmic neutrinos claimed to be observed recently by the IceCube Observatory.
Exotic searches at NA62
Authors: Volpe Roberta
Published: February 2019

The NA62 Experiment, thanks to the high intensity proton beam provided by the SPS, is a suitable apparatus to search for Beyond Standard Model (BSM) scenarios feebly coupled to SM, manifesting itself at the MeV-GeV energy range. In this document a report of Heavy Neutral Lepton and Dark Photons searches results and the prospect for other BSM searches at NA62 are given.
Transverse momentum spectra of mesons in p+p collisions at CERN SPS energies from the UrQMD transport model
Authors: Ozvenchuk Vitalii , Rybicki Andrzej
Published: February 2019

The UrQMD transport model, version 3.4, is used to study the new experimental data on total yields, rapidity distributions and transverse momentum spectra of π±, K±, p and $\bar p$ produced in inelastic p + p interactions at SPS energies, recently published by the NA61/SHINE Collaboration. The comparison of model predictions to these new measurements is presented as a function of collision energy. In addition, we compare with the experimental data the results on kaon-over-pion multiplicity ratio and the inverse slope parameter of negative kaons produced at midrapidity. A complicated pattern of discrepancies between the experimental data and the UrQMD transport model is apparent. We conclude that new experimental data analyzed in this contribution still constitute a challenge for the present version of the model.
Radiative pion capture in 2H, 3He and 3H
Authors: Golak Jacek , Skibiński Roman , Topolnicki Kacper , Witała Henryk , Grassi Alessandro , Kamada Hiroyuki , Nogga Andreas , Elisa Marcucci Laura
Published: February 2019

We investigate the π– + 2H → γ + n + n, π– + 3He → γ + 3H, π– + 3He → γ + n + d, π– + 3He → γ + n + n + p and π– + 3H → γ + n + n + n capture reactions using realistic two-nucleon and three-nucleon potentials and the single nucleon Kroll-Ruderman-type transition operator. We obtain predictions for the total capture rates for all these processes, calculating rigorously the initial and final nuclear states.
Tests of discrete symmetries in positronium decays with the J-PET detector
Authors: Silarski Michał
Published: February 2019

As a relatively simple and purely leptonic state positronium constitutes a unique system to study discrete symmetries with precision limited only by the effects due to the weak interaction and photon-photon scattering. The experimental tests in the positronium decays were performed only on theC, CPandCPTsymmetries with sensitivity much smaller than the predictions which opens a large window to search for phenomena beyond the Standard Model. In this article we present capability of the J-PET detector to improve the current precision of discrete symmetries tests in the decays of positronium atoms.
Semiexclusive production of vector mesons in proton-proton collisions with electromagnetic dissociation of protons
Authors: Cisek Anna , Schäfer Wolfgang , Szczurek Antoni
Published: February 2019

We discuss the semiexclusive production of vector mesons in protonproton collisions with electromagnetic dissociation of one of the protons. Several differential distribution in missing mass (MX), or single-particle variables related exclusively to the produced vector meson are calculated for pp center-of-mass energies 7 and 13 TeV. The cross sections and some differential distributions are compared to their counterparts for purely exclusive reaction $pp \to pV{\rm{ }}p$. For electromagnetic dissociation the important property is that the $p\gamma^{\bigstar} \to Xp$ transitions are given by the electromagnetic structure function of proton. In our calculations we use different parametrizations of the structure function and discuss how it is constrained by the data on virtual photoabsorption on a proton.
Study of the space charge effect in straw tube detectors for the PANDA experiment
Authors: Rathod Narendra , Smyrski Jerzy , Malige Akshay
Published: February 2019

The straw tube detectors in the PANDA experiment will work in high particle fluxes reaching up to 25 kHz/cm2. We performed measurement of the gas gain drop in the PANDA straws due to the space charge effect expected at the high particle fluxes. The applied experimental method and obtained results are presented and are compared with calculations of the gas gain drop based on known mobility of positive ions.
Measurement of the proton scalar polarizabilities at MAMI
Authors: Mornacchi Edoardo
Published: February 2019

The electric (αE1) and magnetic (βM1) scalar polarizabilities describe the response of the nucleon to an applied electric or magnetic field. They are not only fundamental properties related to the internal structure and dynamics of the nucleon, but they are important also in other areas of physics, such as atomic structure. The values of αE1 and βM1 quoted by the Particle Data Group were determined using data on the unpolarized differential cross-section of the Compton scattering $\gamma p \to \gamma p$. The measurement of the beam asymmetry Σ3, provides an alternative approach to the extraction of the scalar polarizabilities, with different sensitivity and systematics compared to the unpolarized crosssection. This asymmetry was measured recently for the first time below the pion photoproduction threshold by the A2 Collaboration with the Crystal Ball/TAPS experiment at MAMI (Mainz, Germany). A new high precision measurement of both a unpolarized cross-section and beam asymmetry Σ3a is ongoing at MAMI and the polarizabilities αE1 and βM1 will be extracted with unprecedented precision.
Evaluation research using astronomy theatre suggests good promise for young Spanish-origin women to choose science majors
Authors: Corbally Christopher , Rappaport Margaret Boone
Published: February 2019

We report evaluation findings and best practices from a morning of research with senior class students at an all-Spanish-origin, secondary school in the southwest United States. We found a jump in interest toward science for the women who self-identified as humanities students, and over the morning, surprisingly, this affected their remembrance of previous attitudes. Our results for this and other evaluations corroborate that experiential activities involving one-to-one or group activities are useful in attracting high school and college students to the sciences, especially young women. These results also pointed toward best practices.