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Study of Top Quark FCNC
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作者 M.Mohammadi Najafabadi N.Tazik 《Communications in Theoretical Physics》 SCIE CAS CSCD 2009年第10期662-664,共3页
We study the one-loop contribution of the effective flavor changing neutral couplings (FCNC) tcZ on the charm quark electric dipole moment. Using the known limits on the top and charm quarks electric dipole moments,... We study the one-loop contribution of the effective flavor changing neutral couplings (FCNC) tcZ on the charm quark electric dipole moment. Using the known limits on the top and charm quarks electric dipole moments, we place limits on these FCNC anomalous couplings. 展开更多
关键词 top quark flavor changing neutral current
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The Investigation Capability of Plasma Focus Device for 13N Radioisotope Production by Means of Deuteron Experimental Spectrum
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作者 Maryam Saed Mahmud Vahdat Roshan +1 位作者 Ayoub Banoushi Morteza Habibi 《Journal of Modern Physics》 2016年第12期1512-1518,共7页
Optimal condition for <sup>13</sup>N radioisotope production through <sup>12</sup>C (d,n) 13N within plasma focus device is investigated. As the deuteron spectrum follows the empirical power la... Optimal condition for <sup>13</sup>N radioisotope production through <sup>12</sup>C (d,n) 13N within plasma focus device is investigated. As the deuteron spectrum follows the empirical power law of the form E<sup>-m</sup>, it is shown that the activity decreases by increasing the value of m. Unlike the fact that the repetition rate increases the activity, it is possible to achieve higher activities by increasing the bombardment time at a fixed repetition rate. 展开更多
关键词 Positron Emission Tomography (PET) Plasma Focus Deuteron Spectrum ACTIVATION Repetition Rate
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Space charge-driven resonant beam halo in high-intensity hadron synchrotrons
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作者 Jia-Yin Du Yao-Shuo Yuan +3 位作者 Morteza Aslaninejad Jing-Tong Du Ming-Yang Huang Sheng Wang 《Nuclear Science and Techniques》 2025年第11期131-148,共18页
With the significant development of high-intensity hadron(proton and heavy ion)accelerator facilities,the space charge effect has become a major limiting factor for increasing beam intensity because it can drive parti... With the significant development of high-intensity hadron(proton and heavy ion)accelerator facilities,the space charge effect has become a major limiting factor for increasing beam intensity because it can drive particle resonance,forming beam halos and causing beam quality degradation or even beam loss.In studies on space charge,the particle-core model(PCM)has been widely adopted to describe halo particle formation.In this paper,we generalize the conventional PCM to include dispersion to investigate the physical mechanism of the beam halo in high-intensity synchrotrons.In particular,a“1:1 parametric resonance”driven by the combined effects of space charge and dispersion is identified.A large dispersion is proven to have a damping effect on the 2:1 parametric resonance.The analysis based on the generalized PCM agrees with particle-in-cell simulations.A beam halo with large mismatch oscillations is also discussed. 展开更多
关键词 Particle core model Space charge Beam halo
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Heavy Charged Gauge Bosons with General CP Violating Couplings
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作者 Mojtaba Mohammadi Najafabadi 《Communications in Theoretical Physics》 SCIE CAS CSCD 2010年第6期1137-1139,共3页
Heavy gauge bosons such as W' are expected to exist in many extensions of the Standard Model. In this paper, the most general Lagrangian for the interaction of W' with top and bottom quarks is considered. This Lagra... Heavy gauge bosons such as W' are expected to exist in many extensions of the Standard Model. In this paper, the most general Lagrangian for the interaction of W' with top and bottom quarks is considered. This Lagrangian consists of V- A and V + A structure with in general complex couplings. Such interactions produce an Electric Dipole Moment (EDM) for the top quark at one loop level. We predict the allowed ranges for the mass and couplings of W' by using the upper limit on the top quark EDM. 展开更多
关键词 heavy gauge boson electric dipole moment
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Research and development of the back-end electronics for the two-dimensional improved resistive plate chambers in CMS upgrade
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作者 P.Cao Z-A.Liu +109 位作者 J.Zhao H.Kou J.Tao J.Song W.Gong N.Wang A.Samalan M.Tytgat N.Zaganidis G.A.Alves F.Marujo F.Torres.Da.S.ilva.De.Araujo E.M.Da Costa D.De Jesus Damiao H.Nogima A.Santoro S.Fonseca De Souza A.Aleksandrov R.Hadjiiska P.Iaydjiev M.Rodozov M.Shopova G.Sultanov M.Bonchev A.Dimitrov L.Litov B.Pavlov P.Petkov A.Petrov S.J.Qian C.Bernal A.Cabrera J.Fraga A.Sarkar S.Elsayed Y.Assran M.El Sawy M.A.Mahmoud Y.Mohammed X.Chen C.Combaret M.Gouzevitch G.Grenier I.Laktineh L.Mirabito K.Shchablo I.Bagaturia D.Lomidze I.Lomidze V.Bhatnagar R.Gupta P.Kumari J.Singh V.Amoozegar B.Boghrati M.Ebraimi R.Ghasemi M.Mohammadi Najafabadi E.Zareian M.Abbrescia R.Aly W.Elmetenawee N.De Filippis A.Gelmi G.Iaselli S.Leszki F.Loddo I.Margjeka G.Pugliese D.Ramos L.Benussi S.Bianco D.Piccolo S.Buontempo A.Di Crescenzo F.Fienga G.De Lellis L.Lista S.Meola P.Paolucci A.Braghieri P.Salvini P.Montagna C.Riccardi P.Vitulo B.Francois T.J.Kim J.Park S.Y.Choi B.Hong K.S.Lee J.Goh H.Lee J.Eysermans C.Uribe Estrada I.Pedraza H.Castilla-Valdez A.Sanchez-Hernandez C.A.Mondragon Herrera D.A.Perez Navarro G.A.Ayala Sanchez S.Carrillo E.Vazquez A.Radi A.Ahmad I.Asghar H.Hoorani S.Muhammad M.A.Shah I.Crotty 《Radiation Detection Technology and Methods》 CSCD 2021年第2期181-191,共11页
Purpose To complement and ensure redundancy in the endcap muon system of the Compact Muon Solenoid(CMS)detector and to extend the Resistive Plate Chamber(RPC)system coverage,improved RPCs(iRPCs)with either orthogonal ... Purpose To complement and ensure redundancy in the endcap muon system of the Compact Muon Solenoid(CMS)detector and to extend the Resistive Plate Chamber(RPC)system coverage,improved RPCs(iRPCs)with either orthogonal layer strips with one-end electronics or single layer strips with two-end electronics providing more precise time measurement will be installed in the very forward pseudorapidity region of|η|<2.4.The iRPC readout system needs to support twodimensional(2D)or two-end readout.In addition,it must combine detector data with Timing,Trigger and fast Control(TTC)and Slow Control(SC)into one data stream over a bi-directional optical link with a line rate of 4.8 Gb/s between the Front-End Electronics(FEE)and the Back-End Electronics(BEE).To fulfill these requirements,a prototype BEE for the iRPC 2D chamber has been researched and designed.Methods A Micro-Telecommunication and Computing Architecture(μTCA)-based processing card was designed in this study to establish a prototype system together with aμTCA crate.The Giga-Bit Transceiver(GBT)protocol is integrated to provide bi-directional communication between the FEE and BEE.A server is connected with the BEE by a Gigabit Ethernet(GbE)link for SC and a 10-GbE link for Data AcQuisition(DAQ).Results The Bit Error Rate(BER)test of the back-end board and a joint test with the iRPC 2D prototype chamber were performed.ABERof less than 1.331×10−16 was obtained.The timemeasurement with a resolution of 3.05 nswas successfully realized,and detector efficiencies of 97.7%for longitudinal strips and 96.0%for orthogonal strips were measured.Test results demonstrate the correctness and reliability of the prototype BEE.Conclusion The BEE prototype satisfies the requirements for the iRPC 2D chamber,and it worked stably and reliably during a long-term joint test run. 展开更多
关键词 CMS iRPC TTC SC BEE μTCA GBT DAQ
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Research and development of time resolution and time reference adjustment for CMS improved resistive plate chambers(iRPCs)
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作者 J.Song J.Zhao +104 位作者 Q.Hou W.Diao P.Cao H.Kou W.Gong N.Wang Z.-A.Liu A.Samalan M.Tytgat G.A.Alves F.Marujo E.A.Coelho E.M.Da Costa H.Nogima A.Santoro S.Fonseca De Souza D.De Jesus Damiao M.Thiel K.Mota Amarilo M.Barroso Ferreira Filho A.Aleksandrov R.Hadjiiska P.Iaydjiev M.Shopova G.Soultanov A.Dimitrov L.Litov B.Pavlov P.Petkov A.Petrov E.Shumka S.J.Qian C.Avila D.Barbosa A.Cabrera A.Florez J.Fraga J.Reyes Y.Assran M.A.Mahmoud I.Crotty R.Aly I.Laktineh G.Grenier M.Gouzevitch L.Mirabito L.Balleyguier C.Combaret W.Tromeur G.Galbit A.Luciol X.Chen I.Bagaturia I.Lomidze Z.Tsamlaidze O.Kemularia V.Amoozegar B.Boghrati M.Ebraimi M.Mohammad Najafabadi E.Zareian M.Abbrescia G.Iaselli G.Pugliese F.Loddo N.De Filippis D.Ramos L.Benussi S.Bianco D.Piccolo S.Meola S.Buontempo F.Carnevali L.Lista P.Paolucci A.Braghieri P.Salvini P.Montagna C.Riccardi P.Vitulo E.Asilar J.Choi T.J.Kim S.Y.Choi B.Hong K.S.Lee J.Goh Y.Lee C.Uribe Estrada I.Pedraza H.Castilla-Valdez A.Sanchez-Hernandez R.L.Fernandez M.Ramirez-Garcia E.Vazquez M.A.Shah N.Zaganidis A.Radi H.Hoorani S.Muhammad A.Ahmad I.Asghar J.Eysermans F.Torres Da Silva De Araujo the CMS Muon Group 《Radiation Detection Technology and Methods》 CSCD 2024年第4期1604-1613,共10页
Purpose Improved resistive plate chambers(iRPCs)will be installed in the challenging forward region of the compact muon solenoid(CMS)during its Phase-2 upgrade.The design target of iRPC time resolution is 1.5 ns.It wi... Purpose Improved resistive plate chambers(iRPCs)will be installed in the challenging forward region of the compact muon solenoid(CMS)during its Phase-2 upgrade.The design target of iRPC time resolution is 1.5 ns.It will help the Level-1 trigger system distinguish the muons from high backgrounds and improve the trigger efficiency.Studying the time resolution after integrating the new backend electronics boards(BEB)is essential for ensuring timely performance.In this system,a time reference(Tref)signal is distributed by the BEB to several frontend electronics boards(FEB)to reset the time-to-digital converters(TDC).In the CMS experiment,the arrangement of the iRPC chambers and on-chamber FEBs is at different positions,resulting in varying Tref arrival times on the FEB side.This paper describes the measures taken to ensure the time resolution of the single path and adjust the time base for multi-paths.Method Unique designs were implemented in the chamber,FEB,and BEB to ensure a satisfactory time resolution.Tref adjustments for different paths were performed in bunch crossing steps(24.950 ns)in the BEB using shift registers.And the sub-bunch crossing adjustment steps were performed in the FEB using the TDC correction module.Finally,the arrival time differences of Tref on different FEBs were less than 1.25 ns after adjustment.Results The time resolution of the FEB–BEB system was observed to be 32 ps.The time resolution of the chamber FEB–BEB system was first measured and is 554 ps at an iRPC working point of 7200 V.In addition,the Tref arrival time differences of different paths were adjusted from−99.923(−90.113)ns to 0.073(−0.141)ns.Conclusion The test results revealed that the system time resolution and Tref adjustment performed by the BEB met the Phase-2 upgrade goals. 展开更多
关键词 CMS iRPC Backend electronics Time resolution Time reference Adjustment
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R&D of back-end electronics for improved resistive plate chambers for the phase 2 upgrade of the CMS end-capmuon system 被引量:1
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作者 H.Kou Z.-A.Liu +113 位作者 J.Zhao J.Song Q.Hou W.Diao P.Cao W.Gong N.Wang A.Samalan M.Tytgat M.El Sawy G.A.Alves F.Marujo E.A.Coelho F.Torres Da Silva De Araujo E.M.Da Costa H.Nogima A.Santoro S.Fonseca De Souza D.De Jesus Damiao M.Thiel M.Barroso Ferreira Filho K.Mota Amarilo A.Aleksandrov R.Hadjiiska P.Iaydjiev M.Rodozov M.Shopova G.Sultanov A.Dimitrov L.Litov B.Pavlov P.Petkov A.Petrov E.Shumka S.J.Qian C.Avila D.Barbosa A.Cabrera A.Florez J.Fraga J.Reyes Y.Assran M.A.Mahmoud Y.Mohammed I.Laktineh G.Grenier M.Gouzevitch L.Mirabito K.Shchablo C.Combaret W.Tromeur G.Galbit A.Luciol X.Chen I.Bagaturia I.Lomidze Z.Tsamalaidze V.Amoozegar B.Boghrati M.Ebraimi E.Zareian M.Mohammadi Najafabadi M.Abbrescia G.Iaselli G.Pugliese F.Loddo N.De Filippis R.Aly D.Ramos W.Elmetenawee S.Leszki I.Margjeka D.Paesani L.Benussi S.Bianco D.Piccolo S.Meola S.Buontempo F.Carnevali L.Lista P.Paolucci F.Fienga A.Braghieri P.Salvini P.Montagna C.Riccardi P.Vitulo E.Asilar J.Choi T.J.Kim S.Y.Choi B.Hong K.S.Lee H.Y.Oh J.Goh I.Yu C.Uribe Estrada I.Pedraza H.Castilla-Valdez R.L.Fernandez A.Sanchez-Hernandez E.Vazquez M.Ramirez-Garcia N.Zaganidis A.Radi H.Hoorani S.Muhammad A.Ahmad I.Asghar M.A.Shah W.A.Khan J.Eysermans I.Crotty on behalf of the CMS Muon Group 《Radiation Detection Technology and Methods》 CSCD 2022年第3期306-316,共11页
Purpose The Large Hadron Collider(LHC)at European Organization for Nuclear Research is planned to be upgraded to the high luminosity LHC.Increasing the luminosity makes muon triggering reliable and offline reconstructi... Purpose The Large Hadron Collider(LHC)at European Organization for Nuclear Research is planned to be upgraded to the high luminosity LHC.Increasing the luminosity makes muon triggering reliable and offline reconstruction very challenging.To enhance the redundancy of the Compact Muon Solenoid(CMS)Muon system and resolve the ambiguity of track reconstruction in the forward region,an improved Resistive Plate Chamber(iRPC)with excellent time resolution will be installed in the Phase-2 CMS upgrade.The iRPC will be equipped with Front-End Electronics(FEE),which can perform high-precision time measurements of signals from both ends of the strip.New Back-End Electronics(BEE)need to be researched and developed to provide sophisticated functionalities such as interacting with FEE with shared links for fast,slow control(SC)and data,in addition to trigger primitives(TPs)generation and data acquisition(DAQ).Method The BEE prototype uses a homemade hardware board compatible with the MTCA standard,the back-end board(BEB).BEE interacts with FEE via a bidirectional 4.8 Gbps optical paired-link that integrates clock,data,and control information.The clock and fast/slow control commands are distributed from BEB to the FEE via the downlink.The uplink is used for BEB to receive the time information of the iRPC’sfired strips and the responses to the fast/slow control commands.To have a pipelined detector data for clusterfinding operation,recover(DeMux)the time relationship of which is changed due to the transmission protocol for the continuous incoming MUXed data from FEE.Then at each bunch crossing(BX),clusteringfired strips that satisfy time and spatial constraints to generate TPs.Both incoming raw MUXed detector data and TPs in a time window and latency based on the trigger signal are read out to the DAQ system.Gigabit Ethernet(GbE)of SiTCP and commercial 10-GbE are used as link standards for SC and DAQ,respectively,for the BEB to interact with the server.Results The joint test results of the BEB with iRPC and Front-End Board(FEB)show a Bit Error Rate of the transmission links less than 1×10-16,a time resolution of the FEB Time-to-Digital Converter of 16 ps,and the resolution of the time difference between both ends of 160 ps which corresponding a spatial resolution of the iRPC of approximately 1.5 cm.Conclusion Test results showed the correctness and stable running of the BEB prototype,of which the functionalities fulfill the iRPC requirements. 展开更多
关键词 CMS iRPC BEE TP DAQ SC
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Scheme-scale ambiguity in analysis of QCD observable
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作者 A.Mirjalili B.A.Kniehl 《Chinese Physics C》 SCIE CAS CSCD 2010年第9期1523-1526,共4页
The scheme-scale ambiguity that has plagued perturbative analysis in QCD remains on obstacle to making precise tests of the theory.Many attempts have been done to resolve the scale ambiguity.In this regard the BLM,EC,... The scheme-scale ambiguity that has plagued perturbative analysis in QCD remains on obstacle to making precise tests of the theory.Many attempts have been done to resolve the scale ambiguity.In this regard the BLM,EC,PMS and CORGI approaches are more distinct.We try to employ these methods to fix the scale ambiguity at NLO,NNLO and even in more higher order approximations.By optimizing the renormalization scale,there will be a possibility to predicate higher order terms.We present general results for predicted terms at any order,using different optimization methods.Some observable as specific examples will be used to indicate the validity of scale fixing to predicate the higher order terms. 展开更多
关键词 perturbative QCD scheme and scale dependence optimization approach predicted terms
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Jacobi polynomials and non-singlet structure function F_2 (x,Q^2) up to N^3LO
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作者 Ali N.Khorramian S.Atashbar Tehrani 《Chinese Physics C》 SCIE CAS CSCD 2010年第9期1479-1481,共3页
In this paper we present the non-singlet QCD analysis to determine valence quark distribution up to four loop.We obtain the fractional difference between the 4-loop and the 1-,2and 3-loop presentations of xu v (x,Q^2... In this paper we present the non-singlet QCD analysis to determine valence quark distribution up to four loop.We obtain the fractional difference between the 4-loop and the 1-,2and 3-loop presentations of xu v (x,Q^2) and xd v (x,Q^2). 展开更多
关键词 PDFs DIS data QCD fit
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Determination of the strong coupling constant using available experimental data
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作者 S.Atashbar Tehrani A.N.Khorramian 《Chinese Physics C》 SCIE CAS CSCD 2010年第9期1485-1487,共3页
We determine the strong coupling constant α s up to 4-loop in perturbative QCD.Testing QCD requires the measurement of α s over ranges of energy scales.In this analysis,the value of α s is determined from the unpol... We determine the strong coupling constant α s up to 4-loop in perturbative QCD.Testing QCD requires the measurement of α s over ranges of energy scales.In this analysis,the value of α s is determined from the unpolarized structure functions data points by minimizing the χ ^2 function between the theory result and experimental data.Using perturbative QCD calculations from threshold corrections,we obtain α s (M 2 Z ) = 0.1139±0.0020 at N ^3 LO which is in good agreement with the very recently results from the inclusive jet cross section in pp collisions at√ s=1.96 TeV. 展开更多
关键词 strong coupling DIS data N ^3 LO
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Strong Coupling Constants of the Doubly Heavy Spin-1/2 Baryons with Light Pseudoscalar Mesons
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作者 S.Rostami K.Azizi A.R.Olamaei 《Chinese Physics C》 SCIE CAS CSCD 2021年第2期351-364,共14页
The strong coupling constants of hadronic multiplets are fundamental parameters which carry information about the strong interactions among participating particles.These parameters can help us construct the hadron-had... The strong coupling constants of hadronic multiplets are fundamental parameters which carry information about the strong interactions among participating particles.These parameters can help us construct the hadron-hadron strong potential and gain information about the structure of the involved hadrons.Motivated by the recent observation of the doubly charmed cc state by LHCb,we determine the strong coupling constants among the doubly heavy spin-1/2 baryons, Ξ_(QQ′)/(′),Ω_(QQ′)/(′) and light pseudoscalar mesons,π,κ,η and η′within the framework of the light cone QCD sum rules.The obtained results may help experimental groups in analysis of the related data at hadron colliders. 展开更多
关键词 doubly heavy baryons light cone QCD strong coupling constants
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Strong vertices of doubly heavy spin-3/2 baryons with light pseudoscalar mesons
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作者 A.R.Olamaei K.Azizi S.Rostami 《Chinese Physics C》 SCIE CAS CSCD 2021年第11期90-100,共11页
The strong coupling constants are basic quantities that carry information on the strong interactions among the baryon and meson multiplets as well as information on the nature and internal structures of the involved h... The strong coupling constants are basic quantities that carry information on the strong interactions among the baryon and meson multiplets as well as information on the nature and internal structures of the involved hadrons.These parameters are introduced in the transition matrix elements of various decays as main inputs and play key roles in analyses of experimental data including various hadrons.We derive the strong coupling constants among the doubly heavy spin-baryons,and,and light pseudoscalar mesons,π,K,andη,using the light-cone QCD.The values obtained for these constants under study may be used to construct the strong potentials among the doubly heavy spin-3/2 baryons and light pseudoscalar mesons. 展开更多
关键词 strong coupling constants doubly heavy baryons light cone QCD sumrules
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Nucleon/nuclei polarized structure function,using Jacobi polynomials expansion
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作者 A.Mirjalili M.M.Yazdanpanah +1 位作者 F.Taghavi-Shahri S.Atashbar Tehrani 《Chinese Physics C》 SCIE CAS CSCD 2010年第9期1534-1537,共4页
We use the constituent quark model to extract polarized parton distributions and finally polarized nucleon structure function.Due to limited experimental data which do not cover whole (x,Q 2 ) plane and to increase ... We use the constituent quark model to extract polarized parton distributions and finally polarized nucleon structure function.Due to limited experimental data which do not cover whole (x,Q 2 ) plane and to increase the reliability of the fitting,we employ the Jacobi orthogonal polynomials expansion.It will be possible to extract the polarized structure functions for Helium,using the convolution of the nucleon polarized structure functions with the light cone moment distribution.The results are in good agreement with available experimental data and some theoretical models. 展开更多
关键词 perturbative QCD nucleon and nuclei structure function jacobi polynomials
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A minimal model for two-component FIMP dark matter:A basic search
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作者 S. Peyman Zakeri S. Mohammad Moosavi Nejad +1 位作者 Mohammadreza Zakeri S. Yaser Ayazi 《Chinese Physics C》 SCIE CAS CSCD 2018年第7期1-11,共11页
In the multi-component configurations of dark matter phenomenology, we propose a minimal two-component configuration which is an extension of the Standard Model with only three new fields; one scalar and one fermion i... In the multi-component configurations of dark matter phenomenology, we propose a minimal two-component configuration which is an extension of the Standard Model with only three new fields; one scalar and one fermion interact with the thermal soup through Higgs portal, mediated by the other scalar in such a way that the stabilities of dark matter candidates are made simultaneously by an explicit Z2 symmetry. Against the most common freeze-out framework, we look for dark matter particle signatures in the freeze-in scenario by evaluating the relic density and detection signals. A simple distinguishing feature of the model is the lack of dark matter conversion, so the dark matter components act individually and the model can be adapted entirely to both singlet scalar and singlet fermionic models, separately. We find dark matter self-interaction as the most promising approach to probe such feeble models. Although the scalar component satisfies this constraint, the fermionic one refuses it even in the resonant region. 展开更多
关键词 dark matter FIMP
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