检索结果-内蒙古大学图书馆

Possible manifestation of the 2p pionium in particle physics processes

学校读者我要写书评

暂无评论

arXiv 2020年

作者： Lichard, Peter Institute of Physics Research Centre for Computational Physics and Data Processing Silesian University in Opava Opava746 01 Czech Republic Institute of Experimental and Applied Physics Czech Technical University in Prague Prague128 00 Czech Republic

We suggest a few particle physics processes in which excited 2p pionium A′2π may be observed. They include the e+e− → π+π− annihilation, the V 0 → π0+− and K± → π±+− ( = e, µ) decays, and the photoproduction of two neutral pions from nucleons. We analyze available experimental data and find that they, in some cases, indicate the presence of 2p pionium, but do not provide definite proof. Copyright © 2020, The Authors. All rights reserved.

关键词： Hadrons

Pionium as a source of false events in the K → π ν ν¯ decays

学校读者我要写书评

暂无评论

arXiv 2020年

作者： Lichard, Peter Institute of Physics and Research Centre for Computational Physics and Data Processing Silesian University in Opava Opava746 01 Czech Republic Institute of Experimental and Applied Physics Czech Technical University in Prague Prague128 00 Czech Republic

We suggest that the unexpected rare KL decay events that appeared in the KOTO experiment can be explained by accounting for pionia (A2π) that were produced in the KL → π0 A2π decays and escaped (a very small portion of them) the decay volume before decaying into two π0s. Agreement with the observation is reached when one assumes that the participating pionia are those in a 2p state. However, this explanation of the KOTO anomaly has to be abandoned because of the disagreement with the NA62 upper limit. The false events rate caused by the 1s pionia is also calculated and shown to constitute only a small ( Copyright © 2020, The Authors. All rights reserved.

关键词：

Improved ranking statistics of the GstLAL inspiral search for compact binary coalescences

学校读者我要写书评

暂无评论

Physical Review D 2023年第4期108卷 043004-043004页

作者： Leo Tsukada Prathamesh Joshi Shomik Adhicary Richard George Andre Guimaraes Chad Hanna Ryan Magee Aaron Zimmerman Pratyusava Baral Amanda Baylor Kipp Cannon Sarah Caudill Bryce Cousins Jolien D. E. Creighton Becca Ewing Heather Fong Patrick Godwin Reiko Harada Yun-Jing Huang Rachael Huxford James Kennington Soichiro Kuwahara Alvin K. Y. Li Duncan Meacher Cody Messick Soichiro Morisaki Debnandini Mukherjee Wanting Niu Alex Pace Cort Posnansky Anarya Ray Surabhi Sachdev Shio Sakon Divya Singh Ron Tapia Takuya Tsutsui Koh Ueno Aaron Viets Leslie Wade Madeline Wade Department of Physics The Pennsylvania State University University Park Pennsylvania 16802 USA Institute for Gravitation and the Cosmos The Pennsylvania State University University Park Pennsylvania 16802 USA Center for Gravitational Physics University of Texas at Austin Austin Texas 78712 USA Department of Physics & Astronomy Louisiana State University Baton Rouge Louisiana 70803 USA Department of Astronomy and Astrophysics The Pennsylvania State University University Park Pennsylvania 16802 USA Institute for Computational and Data Sciences The Pennsylvania State University University Park Pennsylvania 16802 USA LIGO Laboratory California Institute of Technology Pasadena California 91125 USA Leonard E. Parker Center for Gravitation Cosmology and Astrophysics University of Wisconsin-Milwaukee Milwaukee Wisconsin 53201 USA RESCEU The University of Tokyo Tokyo 113-0033 Japan Nikhef Science Park 1098 XG Amsterdam Netherlands Department of Physics University of Illinois Urbana Illinois 61801 USA Graduate School of Science The University of Tokyo Tokyo 113-0033 Japan MIT Kavli Institute for Astrophysics and Space Research Massachusetts Institute of Technology Cambridge Massachusetts 02139 USA Institute for Cosmic Ray Research The University of Tokyo 5-1-5 Kashiwanoha Kashiwa Chiba 277-8582 Japan NASA Marshall Space Flight Center Huntsville Alabama 35811 USA Center for Space Plasma and Aeronomic Research University of Alabama in Huntsville Huntsville Alabama 35899 USA School of Physics Georgia Institute of Technology Atlanta Georgia 30332 USA Concordia University Wisconsin Mequon Wisconsin 53097 USA Department of Physics Hayes Hall Kenyon College Gambier Ohio 43022 USA

Starting from May 2023, the LIGO Scientific, Virgo and KAGRA Collaboration has been conducting the fourth observing run with improved detector sensitivities and an expanded detector network including KAGRA. Accordingly, it is vital to optimize the detection algorithm of low-latency search pipelines, increasing their sensitivities to gravitational waves from compact binary coalescences. In this work, we discuss several new features developed for ranking statistics of GstLAL-based inspiral pipeline, which mainly consist of the signal contamination removal, the bank-ξ2 incorporation, the upgraded ρ−ξ2 signal model, and the integration of KAGRA. An injection study demonstrates that these new features improve the pipeline’s sensitivity by approximately 15% to 20%, paving the way to further multimessenger observations during the upcoming observing run.

关键词： Gravitational waves

Observation of spectral lines in the exceptional GRB 221009A

学校读者我要写书评

暂无评论

arXiv 2024年

作者： Zhang, Yan-Qiu Xiong, Shao-Lin Mao, Ji-Rong Zhang, Shuang-Nan Xue, Wang-Chen Zheng, Chao Liu, Jia-Cong Zhang, Zhen Wang, Xi-Lu Ge, Ming-Yu Yi, Shu-Xu Song, Li-Ming An, Zheng-Hua Cai, Ce Li, Xin-Qiao Peng, Wen-Xi Tan, Wen-Jun Wang, Chen-Wei Wen, Xiang-Yang Wang, Yue Xiao, Shuo Zhang, Fan Zhang, Peng Zheng, Shi-Jie Key Laboratory of Particle Astrophysics Institute of High Energy Physics Chinese Academy of Sciences Beijing100049 China University of Chinese Academy of Sciences Beijing100049 China Yunnan Observatories Chinese Academy of Sciences Yunnan Province Kunming650011 China Center for Astronomical Mega-Science Chinese Academy of Sciences Beijing100012 China Key Laboratory for the Structure and Evolution of Celestial Objects Chinese Academy of Sciences Kunming650216 China College of Physics Hebei Key Laboratory of Photophysics Research and Application Hebei Normal University Hebei Shijiazhuang050024 China Guizhou Provincial Key Laboratory of Radio Astronomy and Data Processing Guizhou Normal University Guiyang550001 China College of Electronic and Information Engineering Tongji University Shanghai201804 China

As the brightest gamma-ray burst ever observed, GRB 221009A provided a precious opportunity to explore spectral line features. In this paper, we performed a comprehensive spectroscopy analysis of GRB 221009A jointly with GECAM-C and Fermi/GBM data to search for emission and absorption lines. For the first time we investigated the line feature throughout this GRB including the most bright part where many instruments suffered problems, and identified prominent emission lines in multiple time intervals. The central energy of the Gaussian emission line evolves from about 37 MeV to 6 MeV, with a nearly constant ratio (about 10%) between the line width and central energy. Particularly, we find that both the central energy and the energy flux of the emission line evolve with time as a power law decay with power law index of -1 and -2 respectively. We suggest that the observed emission lines most likely origin from the blue-shifted electron positron pair annihilation 511 keV line. We find that a standard high latitude emission scenario cannot fully interpret the observation, thus we propose that the emission line comes from some dense clumps with electron positron pairs traveling together with the jet. In this scenario, we can use the emission line to directly, for the first time, measure the bulk Lorentz factor of the jet (Γ) and reveal its time evolution (i.e. Γ ∼ t−1) during the prompt emission. Interestingly, we find that the flux of the annihilation line in the co-moving frame keeps constant. These discoveries of the spectral line features shed new and important lights on the physics of GRB and relativistic jet. Copyright © 2024, The Authors. All rights reserved.

关键词： Gamma rays

Searching for gravitational-wave signals from precessing black hole binaries with the GstLAL pipeline

学校读者我要写书评

暂无评论

arXiv 2024年

作者： Schmidt, Stefano Caudill, Sarah Creighton, Jolien D.E. Magee, Ryan Tsukada, Leo Adhicary, Shomik Baral, Pratyusava Baylor, Amanda Cannon, Kipp Cousins, Bryce Ewing, Becca Fong, Heather George, Richard N. Godwin, Patrick Hanna, Chad Harada, Reiko Huang, Yun-Jing Huxford, Rachael Joshi, Prathamesh Kennington, James Kuwahara, Soichiro Li, Alvin K.Y. Meacher, Duncan Messick, Cody Morisaki, Soichiro Mukherjee, Debnandini Niu, Wanting Pace, Alex Posnansky, Cort Ray, Anarya Sachdev, Surabhi Sakon, Shio Singh, Divya Tapia, Ron Tsutsui, Takuya Ueno, Koh Viets, Aaron Wade, Leslie Wade, Madeline Nikhef Science Park 105 Amsterdam1098 XG Netherlands Utrecht University Princetonplein 1 Utrecht3584 CC Netherlands Department of Physics University of Massachusetts DartmouthMA02747 United States Center for Scientific Computing and Data Science Research University of Massachusetts DartmouthMA02747 United States Leonard E. Parker Center for Gravitation Cosmology and Astrophysics University of Wisconsin-Milwaukee MilwaukeeWI53201 United States LIGO Laboratory California Institute of Technology PasadenaCA91125 United States Department of Physics The Pennsylvania State University University ParkPA16802 United States Institute for Gravitation and the Cosmos The Pennsylvania State University University ParkPA16802 United States RESCEU The University of Tokyo Tokyo113-0033 Japan Department of Physics University of Illinois UrbanaIL61801 United States Department of Physics and Astronomy University of British Columbia VancouverBCV6T 1Z4 Canada Graduate School of Science The University of Tokyo Tokyo113-0033 Japan Center for Gravitational Physics University of Texas at Austin AustinTX78712 United States LIGO Laboratory California Institute of Technology MS 100-36 PasadenaCA91125 United States Department of Astronomy and Astrophysics The Pennsylvania State University University ParkPA16802 United States Institute for Computational and Data Sciences The Pennsylvania State University University ParkPA16802 United States MIT Kavli Institute for Astrophysics and Space Research Massachusetts Institute of Technology CambridgeMA02139 United States Institute for Cosmic Ray Research The University of Tokyo 5-1-5 Kashiwanoha Chiba Kashiwa277-8582 Japan NASA Marshall Space Flight Center HuntsvilleAL35811 United States Center for Space Plasma and Aeronomic Research University of Alabama in Huntsville HuntsvilleAL35899 United States School of Physics Georgia Institute of Technology AtlantaGA30332 United States Concordia University

Precession in Binary Black Holes (BBH) is caused by the failure of the Black Hole spins to be aligned and its study can open up new perspectives in gravitational waves (GW) astronomy, providing, among other advancements, a precise measure of distance and an accurate characterization of the BBH spins. However, detecting precessing signals is a highly non-trivial task, as standard matched filtering pipelines for GW searches are built on many assumptions that do not hold in the precessing case. This work details the upgrades made to the GstLAL pipeline to facilitate the search for precessing BBH signals. The implemented changes in the search statistics and in the signal consistency test are then described in detail. The performance of the upgraded pipeline is evaluated through two extensive searches of precessing signals, targeting two different regions in the mass space, and the consistency of the results is examined. Additionally, the benefits of the upgrades are assessed by comparing the sensitive volume of the precessing searches with two corresponding traditional aligned-spin searches. While no significant sensitivity improvement is observed for precessing binaries with mass ratio q 6, a volume increase of up to 100% is attainable for heavily asymmetric systems with largely misaligned spins. Furthermore, our findings suggest that the primary cause of degraded performance in an aligned-spin search targeting precessing signals is not a poor signal-to-noise-ratio recovery but rather the failure of the ξ2 signal-consistency test. Our work paves the way for a large-scale search for precessing signals, which could potentially result in exciting future detections. © 2024, CC BY.

关键词： Matched filters

Template bank for sub solar mass compact binary mergers in the fourth observing run of Advanced LIGO, Advanced Virgo, and KAGRA

学校读者我要写书评

暂无评论

arXiv 2024年

作者： Hanna, Chad Kennington, James Niu, Wanting Sakon, Shio Singh, Divya Adhicary, Shomik Baral, Pratyusava Baylor, Amanda Cannon, Kipp Caudill, Sarah Cousins, Bryce Creighton, Jolien D.E. Ewing, Becca Fong, Heather George, Richard N. Godwin, Patrick Harada, Reiko Huang, Yun-Jing Huxford, Rachael Joshi, Prathamesh Kuwahara, Soichiro Li, Alvin K.Y. Magee, Ryan Meacher, Duncan Messick, Cody Morisaki, Soichiro Mukherjee, Debnandini Pace, Alexander Posnansky, Cort Ray, Anarya Sachdev, Surabhi Schmidt, Stefano Shah, Urja Tapia, Ron Tsukada, Leo Ueno, Koh Viets, Aaron Wade, Leslie Wade, Madeline Yarbrough, Zach Zhang, Noah Department of Physics The Pennsylvania State University University ParkPA16802 United States Institute for Gravitation and the Cosmos The Pennsylvania State University University ParkPA16802 United States Department of Astronomy and Astrophysics The Pennsylvania State University University ParkPA16802 United States Institute for Computational and Data Sciences The Pennsylvania State University University ParkPA16802 United States Department of Physics University of California BerkeleyCA94720 United States Leonard E. Parker Center for Gravitation Cosmology and Astrophysics University of Wisconsin-Milwaukee MilwaukeeWI53201 United States RESCEU The University of Tokyo Tokyo113-0033 Japan Department of Physics University of Massachusetts DartmouthMA02747 United States Center for Scientific Computing and Data Science Research University of Massachusetts DartmouthMA02747 United States Department of Physics University of Illinois UrbanaIL61801 United States Department of Physics and Astronomy University of British Columbia VancouverBCV6T 1Z4 Canada Graduate School of Science The University of Tokyo Tokyo113-0033 Japan Center for Gravitational Physics University of Texas at Austin AustinTX78712 United States LIGO Laboratory California Institute of Technology MS 100-36 PasadenaCA91125 United States LIGO Laboratory California Institute of Technology PasadenaCA91125 United States MIT Kavli Institute for Astrophysics and Space Research Massachusetts Institute of Technology CambridgeMA02139 United States Institute for Cosmic Ray Research The University of Tokyo 5-1-5 Kashiwanoha Chiba Kashiwa277-8582 Japan NASA Marshall Space Flight Center HuntsvilleAL35811 United States Center for Space Plasma and Aeronomic Research University of Alabama in Huntsville HuntsvilleAL35899 United States Center of Interdisciplinary Education and Research in Astrophysics Northwestern University IL60201 United States School of Physics Georgia Insti

Matched-filtering searches for gravitational-wave signals from compact binary mergers employ template banks which are a collection of modeled waveforms described by unique intrinsic parameters. We present two banks designed for low-latency and archive sub-solar mass (SSM) searches in data from the fourth observing run of LIGO-Virgo-KAGRA, and demonstrate the efficacy of the banks via simulated signals. Further, we introduce a set of modifications to the geometric, manifold algorithm [1, 2] that allow the method to work for exceedingly low component masses necessary for SSM bank production. The archive search bank contains a total of 3,452,006 templates, and covers a mass parameter space of 0.2 to 10 M☉ in the larger component and 0.2 to 1.0 M☉ in the smaller component, the spin parameter space of −0.9 to 0.9 for masses above 0.5 M☉ and −0.1 to 0.1 for masses below 0.5 M☉, and the mass ratio parameter space of 1 to 10. The PSD used was from a week of the first half of the fourth observing run of Advanced LIGO, Advanced Virgo, and KAGRA, and the low frequency cutoff was set to 45 Hz with a maximum waveform duration of 128 seconds. The bank simulations performed using SBank have shown that the banks presented in this paper have sufficient efficacy for use in their respective searches. Copyright © 2024, The Authors. All rights reserved.

关键词： Gravity waves

Magnetar emergence in a peculiar gamma-ray burst from a compact star merger

学校读者我要写书评

暂无评论

National Science Review 2025年第03期 125-131页

作者： Hui Sun Chenwei Wang Jun Yang Bin-Bin Zhang Shaolin Xiong Yi-Han Iris Yin Yuan Liu Ye Li Wangchen Xue Zhen-Yu Yan Chen Zhang Wenjun Tan Haiwu Pan Jiacong Liu Huaqing Cheng Yanqiu Zhang Jingwei Hu Chao Zheng Zhenghua An Ce Cai Zhiming Cai Lei Hu Chichuan Jin Dongyue Li Xinqiao Li Heyang Liu Mingjun Liu Wenxi Peng Liming Song Shengli Sun Xiaojin Sun Xilu Wang Xiangyang Wen Shuo Xiao Shuxu Yi Fan Zhang Wenda Zhang Xiaofeng Zhang Yonghe Zhang Donghua Zhao Shijie Zheng Zhixing Ling Shuang-Nan Zhang Weimin Yuan Bing Zhang National Astronomical Observatories Chinese Academy of Sciences Key Laboratory of Particle Astrophysics Institute of High Energy Physics Chinese Academy of Sciences University of Chinese Academy of Sciences Chinese Academy of Sciences School of Astronomy and Space Science Nanjing University Key Laboratory of Modern Astronomy and Astrophysics (Nanjing University) Ministry of Education Purple Mountain Observatory Chinese Academy of Sciences College of Physics and Hebei Key Laboratory of Photophysics Research and Application Hebei Normal University Innovation Academy for Microsatellites Chinese Academy of Sciences Shanghai Institute of Technical Physics Chinese Academy of Sciences Guizhou Provincial Key Laboratory of Radio Astronomy and Data Processing Guizhou Normal University Nevada Center for Astrophysics University of Nevada Department of Physics and Astronomy University of Nevada

The central engine that powers gamma-ray bursts（GRBs）, the most powerful explosions in the universe, is still not identified. Besides hyper-accreting black holes, rapidly spinning and highly magnetized neutron stars, known as millisecond magnetars, have been suggested to power both long and short GRBs. The presence of a magnetar engine following compact star mergers is of particular interest as it would provide essential constraints on the poorly understood equation of state for neutron stars. Indirect indications of a magnetar engine in these merger sources have been observed in the form of plateau features present in the X-ray afterglow light curves of some short GRBs. Additionally, some X-ray transients lacking gamma-ray bursts have been identified as potential magnetar candidates originating from compact star ***, smoking-gun evidence is still lacking for a magnetar engine in short GRBs, and associated theoretical challenges have been raised. Here we present a comprehensive analysis of the broad-band prompt emission data of the peculiar, very bright GRB 230307A. Despite its apparently long duration, the prompt emission and host galaxy properties are consistent with a compact star merger origin, as suggested by its association with a kilonova. Intriguingly, an extended X-ray emission component shows up as theγ-ray emission dies out, signifying the likely emergence of a magnetar central engine. We also identify an achromatic temporal break in the high-energy band during the prompt emission phase, which was never observed in previous bursts and reveals a narrow jet with a half opening angle of ~ 3.4°(RGRB/1015cm)-1/2,where RGRBis the GRB prompt emission radius.

关键词：

Analysis of GWTC-3 with fully precessing numerical relativity surrogate models

学校读者我要写书评

暂无评论

arXiv 2023年

作者： Islam, Tousif Vajpeyi, Avi Shaik, Feroz H. Haster, Carl-Johan Varma, Vijay Field, Scott E. Lange, Jacob O’Shaughnessy, Richard Smith, Rory Department of Mathematics University of Massachusetts DartmouthMA02747 United States Center for Scientific Computing and Data Science Research University of Massachusetts DartmouthMA02747 United States Department of Statistics The University of Auckland New Zealand School of Physics and Astronomy Monash University VIC3800 Australia OzGrav The ARC Centre of Excellence for Gravitational Wave Discovery ClaytonVIC3800 Australia Department of Physics and Astronomy University of Nevada Las Vegas 4505 South Maryland Parkway Las VegasNV89154 United States Nevada Center for Astrophysics University of Nevada Las VegasNV89154 United States LIGO Laboratory Massachusetts Institute of Technology CambridgeMA02139 United States Department of Physics Kavli Institute for Astrophysics and Space Research Massachusetts Institute of Technology 77 Massachusetts Ave CambridgeMA02139 United States Max Planck Institute for Gravitational Physics Albert Einstein Institute PotsdamD-14476 Germany Center for Computational Relativity and Gravitation Rochester Institute of Technology RochesterNY14623 United States University of Texas AustinTX78712 United States

The third Gravitational-Wave Transient Catalog (GWTC-3) contains 90 binary coalescence candidates detected by the LIGO-Virgo-KAGRA Collaboration (LVK). We provide a re-analysis of binary black hole (BBH) events using a recently developed numerical relativity (NR) waveform surrogate model, NRSur7dq4, that includes all ≤ 4 spin-weighted spherical harmonic modes as well as the complete physical effects of precession. Properties of the remnant black holes’ (BH’s) mass, spin vector, and kick vector are found using an associated remnant surrogate model NRSur7dq4Remnant. Both NRSur7dq4 and NRSur7dq4Remnant models have errors comparable to numerical relativity simulations and allow for high-accuracy parameter estimates. We restrict our analysis to 47 BBH events that fall within the regime of validity of NRSur7dq4 (mass ratios greater than 1/6 and total masses greater than 60M☉). While for most of these events our results match the LVK analyses that were obtained using the semi-analytical models such as IMRPhenomXPHM and SEOBNRv4PHM, we find that for more than 20% of events the NRSur7dq4 model recovers noticeably different measurements of black hole properties like the masses and spins, as well as extrinsic properties like the binary inclination and distance. For instance, GW150914_095045 exhibits noticeable differences in spin precession and spin magnitude measurements. Other notable findings include one event (GW191109_010717) that constrains the effective spin χeff to be negative at a 99.3% credible level and two events (GW191109_010717 and GW200129_065458) with well-constrained kick velocities. Furthermore, compared to the models used in the LVK analyses, NRSur7dq4 recovers a larger signal-to-noise ratio and/or Bayes factors for several events. While these findings have important astrophysical implications, some of the more interesting events are affected by transient detector noise, which can be challenging to remove from short-duration signals. Copyright © 2023, The Au

关键词： Black holes

Minimal Ternary Linear Codes from Vectorial Functions

学校读者我要写书评

暂无评论

arXiv 2024年

作者： Li, Yanjun Kan, Haibin Liu, Fangfang Peng, Jie Zheng, Lijing Zhuo, Zepeng Institute of Statistics and Applied Mathematics Anhui University of Finance and Economics Anhui Bengbu233030 China School of Computer Sciences Fudan University Shanghai200433 China Shanghai Key Laboratory of Intelligent Information Processing School of Computer Science Fudan University Shanghai Engineering Research Center of Blockchain Shanghai Institute for Advanced Communication and Data Science Shanghai200433 China School of Mathematics and Statistics Huaibei Normal University Anhui Huaibei235000 China Mathematics and Science College Shanghai Normal University Guilin Road #100 Shanghai200234 China The School of Mathematics and Physics University of South China Hunan Hengyang421001 China

The study on minimal linear codes has received great attention due to their significant applications in secret sharing schemes and secure two-party computation. Until now, numerous minimal linear codes have been discovered. However, to the best of our knowledge, no infinite family of minimal ternary linear codes was found from vectorial functions. In this paper, we present a necessary and sufficient condition for a large class of ternary linear codes from vectorial functions such that those codes are minimal. Based on that, we construct several minimal ternary linear codes with three-weight from vectorial regular plateaued functions, and determine their weight distributions. Moreover, we also give a necessary and sufficient condition for a large family of ternary linear codes from vectorial functions such that the codes are minimal and violate the AB condition simultaneously. According to this characterization, we find several minimal ternary linear codes violating the AB condition. Notably, our results show that our method can be applied to solve a problem on minimal linear codes proposed by Li et al. Copyright © 2024, The Authors. All rights reserved.

关键词：