An approximately 800 bp cDNA ( Lhcb 2) encoding light_harvesting chlorophyll a/b_binding protein complex (type Ⅱ) was cloned from the seedling of pea ( Pisum sativum L.) with RT_PCR method. Southern blotting usi...An approximately 800 bp cDNA ( Lhcb 2) encoding light_harvesting chlorophyll a/b_binding protein complex (type Ⅱ) was cloned from the seedling of pea ( Pisum sativum L.) with RT_PCR method. Southern blotting using special probe demonstrated that there existed one copy of Lhcb 2 in pea genome. RT_PCR and Northern blotting revealed the expression of Lhcb 2 which was regulated by light in a time_dependent expression manner. The Lhcb 2 gene didn't express untill 2 h after irradiated with white light. Low temperature (4 ℃) also affected the Lhcb 2 gene by decreasing half of its expression under 25 ℃.展开更多
As the LHC beams cannot be polarized,introducing a dense polarized gas target at the LHCb experiment at CERN,to be operated concurrently with beam-beam collisions,will facilitate fixed-target interactions to explore a...As the LHC beams cannot be polarized,introducing a dense polarized gas target at the LHCb experiment at CERN,to be operated concurrently with beam-beam collisions,will facilitate fixed-target interactions to explore a new energy regime of spin physics measurements.Unfortunately,typical surface coatings used to avoid polarization losses,such as water,Teflon,or aluminum,are prohibited due to restrictions imposed by vacuum and beam policies.The former atomic beam source for the polarized target at ANKE@COSY(Forschungszentrum Jülich),an accompanying Lamb-shift polarimeter,and a storage cell chamber inside a superconducting magnet provide a perfect test stand to investigate the properties of a storage cell coated with amorphous carbon.A significant recombination rate,ranging from 93% to 100%,and preservation of polarization during recombination surpassing 74% were observed.We successfully produced H2 molecules with a nuclear polarization of P~0.59.In addition,we could produce polarized H3+ions for the first time and observed the shift of the axis of rotation within HD molecules.展开更多
Heavy flavour physics provides excellent opportunities to indirectly search for new physics at very high energy scales and to study hadron properties for deep understanding of the strong interaction.The LHCb experimen...Heavy flavour physics provides excellent opportunities to indirectly search for new physics at very high energy scales and to study hadron properties for deep understanding of the strong interaction.The LHCb experiment has been playing a leading role in the study of heavy flavour physics since the start of the LHC operations about ten years ago,and made a range of high-precision measurements and unexpected discoveries,which may have far-reaching implications on the field of particle physics.This review highlights a selection of the most influential physics results on CP violation,rare decays,and heavy flavour production and spectroscopy obtained by LHCb using the data collected during the first two operation periods of the LHC.The upgrade plan of LHCb and the physics prospects are also briefly discussed.展开更多
We study the potential of the LHCb 13 TeV single W±and Z boson pseudo-data for constraining the parton distribution functions(PDFs)of the proton.As an example,we demonstrate the sensitivity of the LHCb 13 TeV dat...We study the potential of the LHCb 13 TeV single W±and Z boson pseudo-data for constraining the parton distribution functions(PDFs)of the proton.As an example,we demonstrate the sensitivity of the LHCb 13 TeV data,collected with integrated luminosities of 5fb^(-1)and 300 fb^(-1),to reducing the PDF uncertainty bands of the CT14HERA2 PDFs,using the error PDF updating package EPUMP.The sensitivities of various experimental observables are compared.Generally,sizable reductions in PDF uncertainties can be observed in the 300fb^(-1)data sample,particularly in the small-x region.The double-differential cross section measurement of Z boson pT and rapidity can greatly reduce the uncertainty bands of u and d quarks in almost the whole x range,as compared to various single observable measurements.展开更多
文摘An approximately 800 bp cDNA ( Lhcb 2) encoding light_harvesting chlorophyll a/b_binding protein complex (type Ⅱ) was cloned from the seedling of pea ( Pisum sativum L.) with RT_PCR method. Southern blotting using special probe demonstrated that there existed one copy of Lhcb 2 in pea genome. RT_PCR and Northern blotting revealed the expression of Lhcb 2 which was regulated by light in a time_dependent expression manner. The Lhcb 2 gene didn't express untill 2 h after irradiated with white light. Low temperature (4 ℃) also affected the Lhcb 2 gene by decreasing half of its expression under 25 ℃.
基金funding from the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation)-533904660。
文摘As the LHC beams cannot be polarized,introducing a dense polarized gas target at the LHCb experiment at CERN,to be operated concurrently with beam-beam collisions,will facilitate fixed-target interactions to explore a new energy regime of spin physics measurements.Unfortunately,typical surface coatings used to avoid polarization losses,such as water,Teflon,or aluminum,are prohibited due to restrictions imposed by vacuum and beam policies.The former atomic beam source for the polarized target at ANKE@COSY(Forschungszentrum Jülich),an accompanying Lamb-shift polarimeter,and a storage cell chamber inside a superconducting magnet provide a perfect test stand to investigate the properties of a storage cell coated with amorphous carbon.A significant recombination rate,ranging from 93% to 100%,and preservation of polarization during recombination surpassing 74% were observed.We successfully produced H2 molecules with a nuclear polarization of P~0.59.In addition,we could produce polarized H3+ions for the first time and observed the shift of the axis of rotation within HD molecules.
基金supported by the National Key Research and Development Program of China under Grant Nos.2017YFA0402100 and 2022YFA1601900the National Natural Science Foundation of China(NSFC)under Grant Nos.11435003,11575091,11575094,11925504,11975015,12175245,12175005,11705209,12205312,12275100,11961141015 and 12061141007Chinese Academy of Sciences,Fundamental Research Funds for the Central Universities,Peking University Funds for the New Faculty Startup program.We thank Franz Muheim and Niels Tuning for suggestions in improving the draft.
文摘Heavy flavour physics provides excellent opportunities to indirectly search for new physics at very high energy scales and to study hadron properties for deep understanding of the strong interaction.The LHCb experiment has been playing a leading role in the study of heavy flavour physics since the start of the LHC operations about ten years ago,and made a range of high-precision measurements and unexpected discoveries,which may have far-reaching implications on the field of particle physics.This review highlights a selection of the most influential physics results on CP violation,rare decays,and heavy flavour production and spectroscopy obtained by LHCb using the data collected during the first two operation periods of the LHC.The upgrade plan of LHCb and the physics prospects are also briefly discussed.
基金Supported by the National Natural Science Foundation of China(11875142,11965020)the U.S.National Science Foundation(PHY-2013791.C-P)。
文摘We study the potential of the LHCb 13 TeV single W±and Z boson pseudo-data for constraining the parton distribution functions(PDFs)of the proton.As an example,we demonstrate the sensitivity of the LHCb 13 TeV data,collected with integrated luminosities of 5fb^(-1)and 300 fb^(-1),to reducing the PDF uncertainty bands of the CT14HERA2 PDFs,using the error PDF updating package EPUMP.The sensitivities of various experimental observables are compared.Generally,sizable reductions in PDF uncertainties can be observed in the 300fb^(-1)data sample,particularly in the small-x region.The double-differential cross section measurement of Z boson pT and rapidity can greatly reduce the uncertainty bands of u and d quarks in almost the whole x range,as compared to various single observable measurements.
