The Wilson coefficients of the standard model effective field theory are subject to a series of positivity bounds.It has been shown that while the positivity part of the ultraviolet(UV)partial wave unitarity leads to ...The Wilson coefficients of the standard model effective field theory are subject to a series of positivity bounds.It has been shown that while the positivity part of the ultraviolet(UV)partial wave unitarity leads to the Wilson coefficients living in a convex cone,further including the nonpositivity part caps the cone from above.For Higgs scattering,a capped positivity cone was obtained using a simplified,linear unitarity condition without utilizing the full internal symmetries of Higgs scattering.Here,we further implement stronger nonlinear unitarity conditions from the UV,which generically gives rise to better bounds.We show that,for the Higgs case in particular,while the nonlinear unitarity conditions per se do not enhance the bounds,the fuller use of the internal symmetries do shrink the capped positivity cone significantly.展开更多
Sea surface temperature SST obtained from the initial version of the Korea Operational Oceanographic System(KOOS) SST satellite have low accuracy during summer and daytime. This is attributed to the diurnal warming ...Sea surface temperature SST obtained from the initial version of the Korea Operational Oceanographic System(KOOS) SST satellite have low accuracy during summer and daytime. This is attributed to the diurnal warming effect. Error estimation of SST data must be carried out to use the real-time forecasting numerical model of the KOOS. This study suggests two quality control methods for the KOOS SST system. To minimize the diurnal warming effect, SSTs of areas where wind speed is higher than 5 m/s were used. Depending on the wind threshold value, KOOS SST data for August 2014 were reduced by 0.15°C. Errors in SST data are considered to be a combination of random, sampling, and bias errors. To estimate bias error, the standard deviation of bias between KOOS SSTs and climatology SSTs were used. KOOS SST data yielded an analysis error standard deviation value similar to OSTIA and NOAA NCDC(OISST) data. The KOOS SST shows lower random and sampling errors with increasing number of observations using six satellite datasets. In further studies, the proposed quality control methods for the KOOS SST system will be applied through more long-term case studies and comparisons with other SST systems.展开更多
The Dick effect is one of the main limits to the frequency stability of a passive frequency standard, especially for the fountain clock and ion dock operated in pulsed mode which require unavoidable dead time during i...The Dick effect is one of the main limits to the frequency stability of a passive frequency standard, especially for the fountain clock and ion dock operated in pulsed mode which require unavoidable dead time during interrogation. Here we measure the phase noise of the interrogation oscillator applied in the microwave frequency standard based on laser-cooled 113^Cd+ ions, and analyze the Allan deviation limited by the Dick effect. The results indicate that the Dick effect is one of the key issues for the cadmium ion dock to reach expected frequency stability. This problem can be resolved by interrogating the local oscillator continuously with two ion traps.展开更多
We study two aspects of higher dimensional operators in standard model effective field theory.We first introduce a perturbative power counting rule for the entries in the anomalous dimension matrix of operators with e...We study two aspects of higher dimensional operators in standard model effective field theory.We first introduce a perturbative power counting rule for the entries in the anomalous dimension matrix of operators with equal mass dimension.The power counting is determined by the number of loops and the difference of the indices of the two operators involved,which in turn is defined by assuming that all terms in the standard model Lagrangian have an equal perturbative power.Then we show that the operators with the lowest index are unique at each mass dimension d,i.e.,(H^(†)H)^(d/2)for even d≥4,and(L^(T)εH)C(L^(T)εH)^(T)(H^(†)H)^((d-5)/2)for odd d≥5.Here H,L are the Higgs and lepton doublet,andε,C the antisymmetric matrix of rank two and the charge conjugation matrix,respectively.The renormalization group running of these operators can be studied separately from other operators of equal mass dimension at the leading order in power counting.We compute their anomalous dimensions at one loop for general d and find that they are enhanced quadratically in d due to combinatorics.We also make connections with classification of operators in terms of their holomorphic and anti-holomorphic weights.展开更多
According to National Garment Standardization Technology Committee,three children’s wear standards are going into effect by August 1<sup>st</sup>.Those three standards are as following:Safety Requirementf...According to National Garment Standardization Technology Committee,three children’s wear standards are going into effect by August 1<sup>st</sup>.Those three standards are as following:Safety Requirementfor Rope&Drawstring on Children’s Wear,Safety Requirement forDrawstring on Children’s Upper Outer Garment。展开更多
Electric vehicle(EV)is more environmental-friendly than gasoline vehicle because the main power is not petrol.For the heating system,the waste heat generated by engines is recycled to heat the cabin of gasoline ones,w...Electric vehicle(EV)is more environmental-friendly than gasoline vehicle because the main power is not petrol.For the heating system,the waste heat generated by engines is recycled to heat the cabin of gasoline ones,while the EV need extra electric energy consumption for heating the cabin which decreases the driving range.Personal comfort system(PCS)has been reported that it is an alternative technique to improve occupant thermal comfort and indirectly save building heating energy.This study aims to investigate the occupants’thermal sensation under four heating modes in the EV cabin in winter,including no heating,only PCS,only air conditioning,and both air conditioning and PCS.The field survey is conducted in a parked EV with 12 subjects.Three thermal comfort indexes(PMV,SET^(*),and operative temperature Top)are used and assessed for their applicability in the thermal environment of the EV.Results show that the thermal environment in the cabin is non-uniform and dynamic with the air conditioning mode,while the PCS mode just slightly affects the temperature differences inside.Meanwhile,the subjects’thermal sensations cannot maintain neutral or warmer under the PCS mode only.The results of PMV are lower than the subjects’actual thermal sensation votes(TSV),while the results of SET^(*)and Top show significant linear relationships with the TSV for the correlation coefficients above 0.80.Compare to the air conditioning mode,the neutral SET^(*)and neutral Top are decreased by 2.7℃ and 1.6℃ under the mode with PCS and air conditioning,respectively.The findings indicate that PCS not only has a positive effect on improving the cabin environment and occupant’s thermal sensation but also has the potential to lower the setting temperature of air conditioner of EVs in winter.展开更多
We consider the positivity bounds on dimension-8 four-electron operators and study two related phenomenological aspects at future lepton colliders.First,if positivity is violated,probing such violations will revolutio...We consider the positivity bounds on dimension-8 four-electron operators and study two related phenomenological aspects at future lepton colliders.First,if positivity is violated,probing such violations will revolutionize our understanding of the fundamental pillars of quantum field theory and the S-matrix theory.We observe that positivity violation at scales of 1-10 TeV can potentially be probed at future lepton colliders even if one assumes that dimension-6 operators are also present.Second,the positive nature of the dimension-8 parameter space often allows us to either directly infer the existence of UV-scale particles together with their quantum numbers or exclude them up to certain scales in a model-independent way.In particular,dimension-8 positivity plays an important role in the test of the Standard Model.If no deviations from the Standard Model are observed,it allows for simultaneous exclusion limits on all kinds of potential UV-complete models.Unlike the dimension-6 case,these limits apply regardless of the UV model setup and cannot be removed by possible cancellations among various UV contributions.This thus consists of a novel and universal test to confirm the Standard Model.We demonstrate with realistic examples how all the previously mentioned possibilities,including the test of positivity violation,can be achieved.Hence,we provide an important motivation for studying dimension-8 operators more comprehensively.展开更多
Vector boson scattering at the Large Hadron Collider(LHC)is sensitive to anomalous quartic gauge couplings(aQGCs).In this study,we investigate the aQGC contribution to Wγjj production at the LHC with√s=13 TeV in the...Vector boson scattering at the Large Hadron Collider(LHC)is sensitive to anomalous quartic gauge couplings(aQGCs).In this study,we investigate the aQGC contribution to Wγjj production at the LHC with√s=13 TeV in the context of an effective field theory(EFT).The unitarity bound is applied as a cut on the energy scale of this production process,which is found to have significant suppressive effects on signals.To enhance the statistical significance,we analyze the kinematic and polarization features of the aQGC signals in detail.We find that the polarization effects induced by aQGCs are unique and can discriminate the signals from the SM backgrounds well.With the proposed event selection strategy,we obtain the constraints on the coefficients of dimension-8 operators with current luminosity.The results indicate that the process pp→Wγjj is powerful for searching for the OM2,3,4,5 and OT5,6,7 operators.展开更多
The radiant systems consume less energy and provide better thermal comfort as compared to the conventional system,but the main drawback of radiant technology is inability to cater the latent load and condensation.This...The radiant systems consume less energy and provide better thermal comfort as compared to the conventional system,but the main drawback of radiant technology is inability to cater the latent load and condensation.This problem has engaged researchers to push their emphasis on Personalized Conditioning System(PCS).It forms a micro-climate region near the occupant.This study is aimed at PCS combined with a radiant conditioning system,which evaluates the performance of the PCS and compares it with different radiant cooling systems.A radiant cubicle was used to investigate the performance of the PCS for both heating&cooling modes.For heating mode,the Standard Effective Temperature(SET)was calculated with the help of thermal comfort surveys which were in a range of 23.4℃ to 27.3℃.For cooling mode,four different cases compared the performance of the system which are:Conventional Air Conditioning System(CACS),Radiant Cooled Ceiling System(RCCS),Personalized Radiant Conditioning System(PRCS),and both PRCS-RCCS coupled.It was observed that PRCS alone reaches the thermal comfort criteria with low energy consumption.The energy-saving of RCCS-PRCS was achieved 38%when compared with CACS.It can be concluded that PRCS is a new step in the field of thermal comfort.展开更多
基金supported by the Fundamental Research Funds for the Central Universities(WK2030000036)the National Natural Science Foundation of China(12075233).
文摘The Wilson coefficients of the standard model effective field theory are subject to a series of positivity bounds.It has been shown that while the positivity part of the ultraviolet(UV)partial wave unitarity leads to the Wilson coefficients living in a convex cone,further including the nonpositivity part caps the cone from above.For Higgs scattering,a capped positivity cone was obtained using a simplified,linear unitarity condition without utilizing the full internal symmetries of Higgs scattering.Here,we further implement stronger nonlinear unitarity conditions from the UV,which generically gives rise to better bounds.We show that,for the Higgs case in particular,while the nonlinear unitarity conditions per se do not enhance the bounds,the fuller use of the internal symmetries do shrink the capped positivity cone significantly.
基金A part of the projects titled "Development of Korea Operational Oceanographic System(KOOS),Phase 2","Construction of Ocean Research Stations and their Application Studies","Development of Environmental Information System for NSR Navigation" funded by the Ministry of Oceans and Fisheries,Korea,and "Development of fundamental technology for coastal erosion control" of KIOST
文摘Sea surface temperature SST obtained from the initial version of the Korea Operational Oceanographic System(KOOS) SST satellite have low accuracy during summer and daytime. This is attributed to the diurnal warming effect. Error estimation of SST data must be carried out to use the real-time forecasting numerical model of the KOOS. This study suggests two quality control methods for the KOOS SST system. To minimize the diurnal warming effect, SSTs of areas where wind speed is higher than 5 m/s were used. Depending on the wind threshold value, KOOS SST data for August 2014 were reduced by 0.15°C. Errors in SST data are considered to be a combination of random, sampling, and bias errors. To estimate bias error, the standard deviation of bias between KOOS SSTs and climatology SSTs were used. KOOS SST data yielded an analysis error standard deviation value similar to OSTIA and NOAA NCDC(OISST) data. The KOOS SST shows lower random and sampling errors with increasing number of observations using six satellite datasets. In further studies, the proposed quality control methods for the KOOS SST system will be applied through more long-term case studies and comparisons with other SST systems.
基金Supported by the Young Scientists Fund of the National Natural Science Foundation of China under Grant No 11304177the National Basic Research Program of China under Grant No 2010CB922901
文摘The Dick effect is one of the main limits to the frequency stability of a passive frequency standard, especially for the fountain clock and ion dock operated in pulsed mode which require unavoidable dead time during interrogation. Here we measure the phase noise of the interrogation oscillator applied in the microwave frequency standard based on laser-cooled 113^Cd+ ions, and analyze the Allan deviation limited by the Dick effect. The results indicate that the Dick effect is one of the key issues for the cadmium ion dock to reach expected frequency stability. This problem can be resolved by interrogating the local oscillator continuously with two ion traps.
基金Supported by the National Natural Science Foundation of China under Grant Nos.11025525,11575089the CAS Center for Excellence in Particle Physics(CCEPP)
文摘We study two aspects of higher dimensional operators in standard model effective field theory.We first introduce a perturbative power counting rule for the entries in the anomalous dimension matrix of operators with equal mass dimension.The power counting is determined by the number of loops and the difference of the indices of the two operators involved,which in turn is defined by assuming that all terms in the standard model Lagrangian have an equal perturbative power.Then we show that the operators with the lowest index are unique at each mass dimension d,i.e.,(H^(†)H)^(d/2)for even d≥4,and(L^(T)εH)C(L^(T)εH)^(T)(H^(†)H)^((d-5)/2)for odd d≥5.Here H,L are the Higgs and lepton doublet,andε,C the antisymmetric matrix of rank two and the charge conjugation matrix,respectively.The renormalization group running of these operators can be studied separately from other operators of equal mass dimension at the leading order in power counting.We compute their anomalous dimensions at one loop for general d and find that they are enhanced quadratically in d due to combinatorics.We also make connections with classification of operators in terms of their holomorphic and anti-holomorphic weights.
文摘According to National Garment Standardization Technology Committee,three children’s wear standards are going into effect by August 1<sup>st</sup>.Those three standards are as following:Safety Requirementfor Rope&Drawstring on Children’s Wear,Safety Requirement forDrawstring on Children’s Upper Outer Garment。
基金supported by the Fundamental Research Funds for the Central University of Donghua Universitythe National Natural Science Foundation of China (Grant No.52008079,52278094).
文摘Electric vehicle(EV)is more environmental-friendly than gasoline vehicle because the main power is not petrol.For the heating system,the waste heat generated by engines is recycled to heat the cabin of gasoline ones,while the EV need extra electric energy consumption for heating the cabin which decreases the driving range.Personal comfort system(PCS)has been reported that it is an alternative technique to improve occupant thermal comfort and indirectly save building heating energy.This study aims to investigate the occupants’thermal sensation under four heating modes in the EV cabin in winter,including no heating,only PCS,only air conditioning,and both air conditioning and PCS.The field survey is conducted in a parked EV with 12 subjects.Three thermal comfort indexes(PMV,SET^(*),and operative temperature Top)are used and assessed for their applicability in the thermal environment of the EV.Results show that the thermal environment in the cabin is non-uniform and dynamic with the air conditioning mode,while the PCS mode just slightly affects the temperature differences inside.Meanwhile,the subjects’thermal sensations cannot maintain neutral or warmer under the PCS mode only.The results of PMV are lower than the subjects’actual thermal sensation votes(TSV),while the results of SET^(*)and Top show significant linear relationships with the TSV for the correlation coefficients above 0.80.Compare to the air conditioning mode,the neutral SET^(*)and neutral Top are decreased by 2.7℃ and 1.6℃ under the mode with PCS and air conditioning,respectively.The findings indicate that PCS not only has a positive effect on improving the cabin environment and occupant’s thermal sensation but also has the potential to lower the setting temperature of air conditioner of EVs in winter.
基金CZ is supported by IHEP(Y7515540UI)and National Natural Science Foundation of China(NSFC)(12035008)SYZ acknow ledges suppont from the starting grants from University of Science and Technology of China(K20000089,GG2030040375)+2 种基金is also supported by NSFC(12075233,11947301,12047502)supprted by the Fundamental Rssearch Funds for the Central Universities(WK230000036)This work has been supported by the FCPPL France China Particle Phys-ics Laboratory of the IN2P3/CNRS。
文摘We consider the positivity bounds on dimension-8 four-electron operators and study two related phenomenological aspects at future lepton colliders.First,if positivity is violated,probing such violations will revolutionize our understanding of the fundamental pillars of quantum field theory and the S-matrix theory.We observe that positivity violation at scales of 1-10 TeV can potentially be probed at future lepton colliders even if one assumes that dimension-6 operators are also present.Second,the positive nature of the dimension-8 parameter space often allows us to either directly infer the existence of UV-scale particles together with their quantum numbers or exclude them up to certain scales in a model-independent way.In particular,dimension-8 positivity plays an important role in the test of the Standard Model.If no deviations from the Standard Model are observed,it allows for simultaneous exclusion limits on all kinds of potential UV-complete models.Unlike the dimension-6 case,these limits apply regardless of the UV model setup and cannot be removed by possible cancellations among various UV contributions.This thus consists of a novel and universal test to confirm the Standard Model.We demonstrate with realistic examples how all the previously mentioned possibilities,including the test of positivity violation,can be achieved.Hence,we provide an important motivation for studying dimension-8 operators more comprehensively.
基金Supported in part by the National Natural Science Foundation of China (11905093, 11875157, 11947402)the Doctoral Start-up Foundation of Liaoning Province (2019-BS-154)
文摘Vector boson scattering at the Large Hadron Collider(LHC)is sensitive to anomalous quartic gauge couplings(aQGCs).In this study,we investigate the aQGC contribution to Wγjj production at the LHC with√s=13 TeV in the context of an effective field theory(EFT).The unitarity bound is applied as a cut on the energy scale of this production process,which is found to have significant suppressive effects on signals.To enhance the statistical significance,we analyze the kinematic and polarization features of the aQGC signals in detail.We find that the polarization effects induced by aQGCs are unique and can discriminate the signals from the SM backgrounds well.With the proposed event selection strategy,we obtain the constraints on the coefficients of dimension-8 operators with current luminosity.The results indicate that the process pp→Wγjj is powerful for searching for the OM2,3,4,5 and OT5,6,7 operators.
文摘The radiant systems consume less energy and provide better thermal comfort as compared to the conventional system,but the main drawback of radiant technology is inability to cater the latent load and condensation.This problem has engaged researchers to push their emphasis on Personalized Conditioning System(PCS).It forms a micro-climate region near the occupant.This study is aimed at PCS combined with a radiant conditioning system,which evaluates the performance of the PCS and compares it with different radiant cooling systems.A radiant cubicle was used to investigate the performance of the PCS for both heating&cooling modes.For heating mode,the Standard Effective Temperature(SET)was calculated with the help of thermal comfort surveys which were in a range of 23.4℃ to 27.3℃.For cooling mode,four different cases compared the performance of the system which are:Conventional Air Conditioning System(CACS),Radiant Cooled Ceiling System(RCCS),Personalized Radiant Conditioning System(PRCS),and both PRCS-RCCS coupled.It was observed that PRCS alone reaches the thermal comfort criteria with low energy consumption.The energy-saving of RCCS-PRCS was achieved 38%when compared with CACS.It can be concluded that PRCS is a new step in the field of thermal comfort.