[ProQuest: [...] denotes non US-ASCII text; see PDF]
Bingfang Yang 1 and Zhiyong Liu 1 and Jinzhong Han 2 and Guang Yang 3
Academic Editor:Juan José Sanz-Cillero
1, College of Physics & Electronic Engineering, Henan Normal University, Xinxiang 453007, China
2, School of Physics and Electromechanical Engineering, Zhoukou Normal University, Henan 466001, China
3, Basic Teaching Department, Jiaozuo University, Jiaozuo 454000, China
Received 17 April 2016; Accepted 31 July 2016
This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. The publication of this article was funded by SCOAP3 .
1. Introduction
In July 2012, a Higgs-like resonance with mass mh ~125 GeV has been discovered by the ATLAS and CMS experiments at the Large Hadron Collider (LHC) [1, 2]. So far, all the measurements of the discovered new particle [3-10] are well compatible with the scalar boson predicted by the Standard Model (SM) [11-15].
It is well known that the SM cannot be the final theory of nature. Theoretically, successful explanation of some problems, such as the hierarchy problem, requires new physics beyond the SM near the TeV scale. Experimentally, the solid evidence for neutrino oscillation is one of the firm hints for new physics. The minimal extension of the SM that we consider in this paper is that the SM gauge groups are augmented by a U(1)B-L symmetry, where B and L represent the baryon number and lepton number, respectively. The B-L gauge symmetry can explain the presence of three right-handed neutrinos and provide a natural framework for the seesaw mechanism [16, 17]. In addition, it is worth noting that B-L symmetry breaking can take place at the TeV scale, hence giving rise to new and interesting TeV scale phenomenology.
The Yukawa couplings play an important role in probing the new physics since they are sensitive to new flavor dynamics. The top quark is the heaviest particle discovered and owns the strongest Yukawa coupling. The top quark Yukawa coupling is speculated to be sensitive to the electroweak symmetry breaking (EWSB) mechanism and new physics. The tt-h production process is a golden channel for directly probing the top Yukawa coupling; however, this process cannot provide the information on the relative sign between the coupling of the Higgs to fermions and to vector bosons. As a beneficial supplement, the thj production process can bring a unique possibility [18-21] and many relevant works have been carried out [22-34].
The U(1)B-L model predicts heavy neutrinos, a TeV scale extra neutral gauge boson, and an additional heavy neutral Higgs, which makes the model phenomenologically rich. The heavy Higgs state mixes with the SM Higgs boson so that some Higgs couplings are modified and this effect can also influence the process of single top and Higgs associated production. Besides, the process of single top and heavy Higgs associated production deserves attention, which is equally important for understanding the EWSB and probing new physics. Performing the detailed analysis on this process may provide a good opportunity to probe the U(1)B-L model signal.
The paper is structured as follows. In Section 2 we review the U(1)B-L model related to our work. In Section 3 we first calculate the production cross sections of the single top and h(=H1 ,H2 ) associated production at the LHC and then explore the observability of t-channel process pp[arrow right]tH2 j through pp[arrow right]t([arrow right]qq-[variant prime] b)H2 ([arrow right]4l)j by performing a parton-level simulation. Finally, we make a summary in Section 4.
2. A Brief Review of the U(1)B-L Model
The minimal B-L extension of the SM [35-42] is based on the gauge group SU(3)C ×SU(2)L ×U(1)Y ×U(1)B-L with the classical conformal symmetry. Under this gauge symmetry, the invariance of the Lagrangian implies the existence of a new gauge boson. In order to make the model free from all the gauge and gravitational anomalies, three generations of right-handed neutrinos are necessarily introduced.
The Lagrangian for Yang-Mills and fermionic sectors is given by [figure omitted; refer to PDF] where Fμν =∂μBν -∂νBμ , Fμν[variant prime] =∂μBν[variant prime] -∂νBμ[variant prime] , Bμ and Bμ[variant prime] are, respectively, the U(1)Y and U(1)B-L gauge fields, and the fields' charges are the usual SM and B-L ones. The non-Abelian field strengths not included here are the same as in the SM. In this field basis, the covariant derivative is [figure omitted; refer to PDF]
In this model, the most general gauge-invariant and renormalizable scalar Lagrangian can be expressed as [figure omitted; refer to PDF] with the scalar potential given by [figure omitted; refer to PDF] To determine the condition for the potential to be bounded from below, the couplings λ1 , λ2 , and λ3 should be related as [figure omitted; refer to PDF] We denote the vacuum expectation values (VEVs) of H and χ by v and v[variant prime] , respectively, and the nonzero minimums are given by [figure omitted; refer to PDF] where v and v[variant prime] are the EWSB scale and the B-L symmetry breaking scale, respectively.
From the mass terms in the scalar potential, the mass matrix between the two Higgs bosons in the basis (H,χ) can be given by [figure omitted; refer to PDF] The mass eigenstates are related via the mixing matrix [figure omitted; refer to PDF] where the mixing angle α (-π/2<α<π/2) satisfies [figure omitted; refer to PDF] The masses of the physical Higgs bosons H1 and H2 are given by [figure omitted; refer to PDF] where H1 and H2 are light SM-like and heavy Higgs bosons, respectively.
To complete the discussion on the Lagrangian, we write down the Yukawa term, which in addition to the SM terms has interactions involving the right-handed neutrinos NR : [figure omitted; refer to PDF] where H~=iσ2H[low *] and i,j run within 1~3. The VEV of the χ field breaks the B-L symmetry and generates the Majorana masses for the right-handed neutrinos and the Dirac masses for the light neutrinos.
In terms of the mixing angle α, the couplings of H1 and H2 with the fermions and gauge bosons can be expressed as follows: [figure omitted; refer to PDF] where f denotes the SM fermions and sW =sin[...]θW with θW is the usual Weinberg angle.
3. Numerical Results and Discussions
For the single top and Higgs associated production, the three processes of interest are characterized by the virtuality of the W boson in the process [43]: (i) t-channel, where the W is spacelike; (ii) s-channel, where the W is timelike; (iii) W-associated production channel, where there is emission of a real W boson. In the U(1)B-L model, the lowest-order Feynman diagrams of the t-channel process pp[arrow right]tH1 (H2 )j (j≠b) are shown in Figure 1, the s-channel process pp[arrow right]tH1 (H2 )b- is shown in Figure 2 and the W-associated production channel process pp[arrow right]tH1 (H2 )W- is shown in Figure 3. We can see that the Feynman diagrams for these processes are the same as the corresponding SM processes. Moreover, the conjugate processes where t is replaced by t- have been included in our calculations.
Figure 1: Lowest-order Feynman diagrams for pp[arrow right]tH1 (H2 )j in the U(1)B-L model.
(a) [figure omitted; refer to PDF]
(b) [figure omitted; refer to PDF]
(c) [figure omitted; refer to PDF]
Figure 2: Lowest-order Feynman diagrams for pp[arrow right]tH1 (H2 )b- in the U(1)B-L model.
(a) [figure omitted; refer to PDF]
(b) [figure omitted; refer to PDF]
(c) [figure omitted; refer to PDF]
Figure 3: Lowest-order Feynman diagrams for pp[arrow right]tH1 (H2 )W- in the U(1)B-L model.
(a) [figure omitted; refer to PDF]
(b) [figure omitted; refer to PDF]
(c) [figure omitted; refer to PDF]
(d) [figure omitted; refer to PDF]
(e) [figure omitted; refer to PDF]
(f) [figure omitted; refer to PDF]
(g) [figure omitted; refer to PDF]
(h) [figure omitted; refer to PDF]
We compute the cross sections by using CalcHEP 3.6.25 [44] with the parton distribution function CTEQ6L [45] and set the renormalization scale μR and factorization scale μF to be μR =μF =(mt +mh +mX )/2, (h=H1 ,H2 ; X=j,b,W). The SM input parameters are taken as follows [46]: [figure omitted; refer to PDF]
In our calculations, the relevant U(1)B-L model parameters are the mixing parameter α and the heavy Higgs mass mH2 . Considering the constraints in [47-50], we choose the parameter space as follows: 0.01<sin[...]α<0.4, 250 GeV<=mH2 <=1000 GeV.
3.1. Single Top and H1 Associated Production
In Figure 4, we show the production cross sections of the processes pp[arrow right]tH1 j, pp[arrow right]tH1 b-, and pp[arrow right]tH1W- as a function of sin[...]α at the 8 and 14 TeV LHC in the U(1)B-L model, respectively. For clarity, we marked the corresponding SM process cross sections on the figures. We can see that the cross sections in the U(1)B-L model decrease with increasing sin[...]α. Besides, the behavior of these three processes is similar for the 8 TeV and 14 TeV. This is easy to understand because there is the same change factor cos[...]α in the light Higgs H1 couplings in (12) so that the production cross sections are suppressed by cos2 [...]α; that is, σB-L =σSMcos2 [...]α. When sin[...]α[arrow right]0, the mixing between the light Higgs H1 and the heavy Higgs H2 will decouple so that the cross sections go back to the SM values.
Figure 4: The production cross sections σtH1 j , σtH1 b , σtH1 W as a function of sin[...]α at 8, 14 TeV LHC in the U(1)B-L model.
[figure omitted; refer to PDF]
3.2. Single Top and H2 Associated Production
In Figures 5 and 6, we show the production cross sections of the processes pp[arrow right]tH2 j, pp[arrow right]tH2 b-, and pp[arrow right]tH2W- as a function of sin[...]α at the 8 and 14 TeV LHC in the U(1)B-L model, respectively. In order to see the influence of the heavy Higgs mass mH2 on the production cross sections, we take mH2 =250,500,750,1000 GeV as example. We can see that the cross sections increase with increasing sin[...]α, which is because the heavy Higgs H2 couplings in (12) are proportional to sin[...]α so that the cross sections are proportional to sin2 [...]α.
Figure 5: The production cross sections σtH2 j , σtH2 b , σtH2 W as a function of sin[...]α at 8 TeV LHC in the U(1)B-L model.
[figure omitted; refer to PDF]
Figure 6: The production cross sections σtH2 j , σtH2 b , σtH2 W as a function of sin[...]α at 14 TeV LHC in the U(1)B-L model.
[figure omitted; refer to PDF]
3.3. Observability of pp[arrow right]tH2 j
The t-channel process dominates amongst these three production modes at the LHC, so we will explore the observability through the t-channel pp[arrow right]tH2 j at 14 TeV LHC in the following section. The three most dominant decay modes of the heavy Higgs H2 are WW, H1H1 , and ZZ [51]. Though the branching fraction of H2 [arrow right]ZZ is smaller than the branching fractions of H2 [arrow right]WW and H2 [arrow right]H1H1 , the ZZ signal is much easier to separate from SM backgrounds. For the ZZ decay modes, the leptonic decay mode of ZZ offers the cleanest possible signatures though the dijet and semileptonic decay modes of ZZ are larger. This leptonic decay mode has been studied in the heavy Higgs production at the LHC and it found that a heavy Higgs boson of mass smaller than 500 GeV can be discovered at the LHC with high luminosity (HL-LHC) [50]. In our work, we concentrate on the channel pp[arrow right]t([arrow right]W+ b[arrow right]qq-[variant prime] b)H2 ([arrow right]ZZ[arrow right]l1+l1-l2+l2- )j as shown in Figure 7, where H2 decays to two Z bosons and the two Z bosons subsequently decay to four leptons. The signal is characterized by [figure omitted; refer to PDF] where j denotes the light jets and l=e,μ. The largest background for this process comes from the tZZj production mode that will generate the same final state.
Figure 7: Feynman diagrams for signal pp[arrow right]tH2 j (a) and background pp[arrow right]tZZj (b) including the decay chain with hadronic top quark, leptonic Z boson decay, and Higgs decay H2 [arrow right]ZZ[arrow right]l1+l1-l2+l2- at the LHC.
(a) [figure omitted; refer to PDF]
(b) [figure omitted; refer to PDF]
We generate the signal and background events with MadGraph5 [52] and perform the parton shower and the fast detector simulations with PYTHIA [53] and Delphes [54]. To simulate b-tagging, we take moderate single b-tagging efficiency [...]b =0.7 for b-jet in the final state. Following the analysis on tt-h signature by ATLAS and CMS collaborations [55, 56] at the LHC Run-I, the events are selected to satisfy the criteria as follows: [figure omitted; refer to PDF]
Due to the small signal cross section, this process has a low signal-to-background ratio S/B at the LHC. In this case, we will focus on enhancing the systematic significance S/B. Considering the transverse momentum of the leptons has little effect on the signal-to-background ratio and the systematic significance, we do not use it as selection cuts here. After analysis, we will adopt the following two cuts; the relevant normalized distributions of the kinematic variables for mH2 =250 GeV, sin[...]α=0.3 with respect to the background are shown in Figure 8.
Figure 8: The normalized distributions of HT ,M4l in the signal and background at 14 TeV LHC for mH2 =250 GeV, sin[...]α=0.3, where HT (=∑hadronic particles [...](p[arrow right]T )) is the total transverse hadronic energy.
[figure omitted; refer to PDF]
Firstly, we impose the cut HT <380 GeV to separate signal from background. This cut can improve both the signal-to-background ratio S/B and the systematic significance S/B.
After that, we apply the invariant mass of the four-lepton system to further isolate the signal and let M4l lie in the range mH2 ±20 GeV. We can see that the signal-to-background ratio S/B is improved and the systematic significance S/B is enhanced obviously.
The cut-flow cross sections of the signal and background for 14 TeV LHC are summarized in Table 1. For clarity, we also give the cut efficiency of the signal events in Table 1. After all cuts above, we can see that the systematic significance S/B is substantially improved. For the HL-LHC with a final integrated luminosity of L=3000 fb-1 , the signal-to-background ratio S/B can reach 1.6σ and systematic significance S/B can reach 2.86 for mH2 =250 GeV, sin[...]α=0.3. Furthermore, we can compute the number of of signal events NS and background events NB and find that NS ≈0.9 and NB ≈0.3 for the luminosity of L=3000 fb-1 . Unfortunately, we can see that the number of signal events is very small because of the small leptonic branching ratio of the Z boson, which will be a trouble for detecting this signal at the LHC.
Table 1: Cutflow of the cross sections for the signal and backgrounds at 14 TeV LHC on the benchmark point (mH2 =250 GeV, sin[...]α=0.3). All the conjugate processes of the signal and background have been included.
Cuts | σ (×10-4 fb) | S / B | S / B | S -cut efficiency | |
Signal | Background | 3000 fb-1 | % | ||
t H 2 j | t Z Z j | ||||
No cuts | 34.3 | 103.9 | 1.84 | 0.33 |
|
Basic cuts | 15.6 | 50.2 | 1.20 | 0.31 | 45.5 |
H T < 380 GeV | 11.3 | 19.5 | 1.40 | 0.58 | 72.4 |
| M 4 l - 250 | < 20 GeV | 2.97 | 1.04 | 1.60 | 2.86 | 26.3 |
4. Summary
In the minimal B-L extension of the SM, we investigated the single top and Higgs associated production at the LHC. We computed the production cross sections of the processes pp[arrow right]tH1 (H2 )X (X=j,b,W) for 8, 14 TeV LHC, and displayed the dependance of the cross sections on the relevant U(1)B-L model parameter. Moreover, we investigated the observability of process pp[arrow right]tH2 j followed by the decays t[arrow right]qq-[variant prime] b and H2 ([arrow right]ZZ[arrow right]l1+l1-l2+l2- ) at 14 TeV LHC for mH2 =250 GeV, sin[...]α=0.3. We performed a simple parton-level simulation and found that it is challenging for the 14 TeV LHC and future HL-LHC with the integrated luminosity L=3000 fb-1 to observe the effect of the process pp[arrow right]tH2 j through this final state. So, we have to expect a collider with higher energy and higher luminosity to probe this effect. Maybe, a 100 TeV proton-proton collider with integrated luminosities of 3 ab-1 ~30 ab-1 can provide us with a potential opportunity [57].
Acknowledgments
This work was supported by the National Natural Science Foundation of China (NNSFC) under Grant no. 11405047, the Startup Foundation for Doctors of Henan Normal University under Grant no. qd15207, the Joint Funds of the National Natural Science Foundation of China (U1404113), the Education Department Foundation of Henan Province (14A140010), the Aid Project for the Mainstay Young Teachers in Henan Provincial Institutions of Higher Education of China (2014GGJS-283), and colleges and universities in Henan province key scientific research project for 2016 (16B140002).
[1] G. Aad, B. Abbott, J. Abdallah, "Combined search for the Standard Model Higgs boson using up to 4.9 fb-1 of pp collision data at s=7 TeV with the ATLAS detector at the LHC," Physics Letters B , vol. 710, no. 1, pp. 49-66, 2012.
[2] S. Chatrachyan, V. Khachatryan, A. M. Sirunyan, "Combined results of searches for the standard model Higgs boson in pp collisions at s=7 TeV," Physics Letters B , vol. 710, pp. 26-48, 2012.
[3] G. Aad, T. Abajyan, B. Abbott, "Evidence for the spin-0 nature of the Higgs boson using ATLAS data," Physics Letters B , vol. 726, no. 1-3, pp. 120-144, 2013.
[4] G. Aad, B. Abbott, J. Abdallah, "Measurement of Higgs boson production in the diphoton decay channel in pp collisions at center-of-mass energies of 7 and 8 TeV with the ATLAS detector," Physical Review D , vol. 90, 2014.
[5] G. Aad, B. Abbott, J. Abdallah, "Measurements of Higgs boson production and couplings in the four-lepton channel in pp collisions at center-of-mass energies of 7 and 8 TeV with the ATLAS detector," Physical Review D , vol. 91, 2015.
[6] The ATLAS collaboration, "Search for the bb¯ decay of the Standard Model Higgs boson in associated (W /Z )H production with the ATLAS detector," Journal of High Energy Physics , vol. 2015, article 69, 2015.
[7] V. Khachatryan, A. M. Sirunyan, A. Tumasyan, "Observation of the diphoton decay of the Higgs boson and measurement of its properties," The European Physical Journal C , vol. 74, article 3076, 2014.
[8] S. Chatrchyan, V. Khachatryan, A. M. Sirunyan, "Evidence for the direct decay of the 125 GeV Higgs boson to fermions," Nature Physics , vol. 10, pp. 557-560, 2014.
[9] S. Chatrchyan, V. Khachatryan, A. M. Sirunyan, "Measurement of the properties of a Higgs boson in the four-lepton final state," Physical Review D , vol. 89, no. 9, 2014.
[10] The CMS Collaboration, "Measurement of Higgs boson production and properties in the WW decay channel with leptonic final states," Journal of High Energy Physics , vol. 2014, articlr 96, 2014.
[11] P. W. Higgs, "Broken symmetries, massless particles and gauge fields," Physics Letters , vol. 12, no. 2, pp. 132-133, 1964.
[12] P. W. Higgs, "Broken symmetries and the masses of gauge bosons," Physical Review Letters , vol. 13, pp. 508-509, 1964.
[13] F. Englert, R. Brout, "Broken symmetry and the mass of gauge vector mesons," Physical Review Letters , vol. 13, pp. 321-323, 1964.
[14] G. S. Guralnik, C. R. Hagen, T. W. B. Kibble, "Global conservation laws and massless particles," Physical Review Letters , vol. 13, no. 20, pp. 585-587, 1964.
[15] T. W. B. Kibble, "Symmetry breaking in n-Abelian gauge theories," Physical Review , vol. 155, no. 5, pp. 1554-1561, 1967.
[16] S. Khalil, "Low-scale B-L extension of the standard model," Journal of Physics G: Nuclear and Particle Physics , vol. 35, no. 5, 2008.
[17] S. Khalil, "TeV-scale gauged B-L symmetry with inverse seesaw mechanism," Physical Review D , vol. 82, 2010.
[18] G. Bordes, B. van Eijk, "On the associate production of a neutral intermediate-mass Higgs boson with a single top quark at the LHC and SSC," Physics Letters B , vol. 299, no. 3-4, pp. 315-320, 1993.
[19] T. M. Gould, E. R. Poppitz, "Complex time solutions with nontrivial topology and multiparticle scattering in Yang-Mills theory," Physics Letters. B , vol. 312, no. 3, pp. 299-304, 1993.
[20] W. J. Stirling, D. J. Summers, "Production of an intermediate-mass Higgs boson in association with a single top quark at LHC and SSC," Physics Letters B , vol. 283, no. 3-4, pp. 411-415, 1992.
[21] J. L. Diaz-Cruz, O. A. Sampayo, "Associated production of the Higgs boson with tb at hadron colliders," Physics Letters B , vol. 276, no. 1-2, pp. 211-213, 1992.
[22] V. Barger, M. McCaskey, G. Shaughnessy, "Single top and Higgs associated production at the LHC," Physical Review D , vol. 81, 2010.
[23] M. Farina, C. Grojean, F. Maltoni, E. Salvioni, A. Thamm, "Lifting degeneracies in Higgs couplings using single top production in association with a Higgs boson," Journal of High Energy Physics , vol. 2013, article 22, 2013.
[24] L. Wu, "Enhancing thj production from Top-Higgs FCNC couplings," Journal of High Energy Physics , vol. 2015, article 61, 2015.
[25] A. Kobakhidze, L. Wu, J. Yue, "Anomalous top-Higgs couplings and top polarisation in single top and Higgs associated production at the LHC," Journal of High Energy Physics , vol. 2014, article 100, 2014.
[26] A. Greljo, J. F. Kamenik, J. Kopp, "Disentangling flavor violation in the top-Higgs sector at the LHC," Journal of High Energy Physics , vol. 2014, no. 7, article 046, 2014.
[27] S. Khatibi, M. M. Najafabadi, "Probing the anomalous FCNC interactions in a top-Higgs boson final state and the charge ratio approach," Physical Review D , vol. 89, 2014.
[28] D. Atwood, S. K. Gupta, A. Soni, "Constraining the flavor changing Higgs couplings to the top-quark at the LHC," Journal of High Energy Physics , vol. 2014, article 57, 2014.
[29] J. Chang, K. Cheung, J. S. Lee, C.-T. Lu, "Probing the top-Yukawa coupling in associated Higgs production with a single top quark," Journal of High Energy Physics , vol. 2014, article 62, 2014.
[30] B. F. Yang, J. Z. Han, N. Liu, "Associated production of single top and Higgs at the LHC in the littlest Higgs model with T-parity," Journal of High Energy Physics , vol. 2015, article 148, 2015.
[31] Y. M. Zhang, B. F. Yang, "Single-top and Higgs associated production via the Formula and tHW-channels at the LHC in the LHT model," EPL , vol. 110, no. 2, 2015.
[32] F. Demartin, F. Maltoni, K. Mawatari, M. Zaro, "Higgs production in association with a single top quark at the LHC," European Physical Journal C , vol. 75, no. 6, pp. 267, 2015.
[33] J. Campbell, K. Ellis, R. Röntsch, "Single top production in association with a Z boson at the LHC," Physical Review D , vol. 87, 2013.
[34] P. Agrawal, S. Mitra, A. Shivaji, "Effect of anomalous couplings on the associated production of a single top quark and a Higgs boson at the LHC," Journal of High Energy Physics , vol. 2013, article 77, 2013.
[35] R. N. Mohapatra, R. E. Marshak, "Local B-L symmetry of electroweak interactions, majorana neutrinos, and neutron oscillations," Physical Review Letters , vol. 44, no. 20, pp. 1316-1319, 1980.
[36] R. E. Marshak, R. N. Mohapatra, "Quark-lepton symmetry and B-L as the U(1) generator of the electroweak symmetry group," Physics Letters B , vol. 91, no. 2, pp. 222-224, 1980.
[37] C. Wetterich, "Neutrino masses and the scale of B-L violation," Nuclear Physics B , vol. 187, no. 2, pp. 343-375, 1981.
[38] A. Masiero, J. F. Nieves, T. Yanagida, "B-L violating proton decay and late cosmological baryon production," Physics Letters B , vol. 116, no. 1, pp. 11-15, 1982.
[39] R. N. Mohapatra, G. Senjanovic, "Spontaneous breaking of global B-L symmetry and matter-antimatter oscillations in grand unified theories," Physical Review D , vol. 27, no. 1, pp. 254-263, 1983.
[40] W. Buchmüller, C. Greub, P. Minkowski, "Neutrino masses, neutral vector bosons and the scale of B-L breaking," Physics Letters B , vol. 267, no. 3, pp. 395-399, 1991.
[41] L. Basso, A. Belyaev, S. Moretti, C. H. Shepherd-Themistocleous, "Phenomenology of the minimal B-L extension of the standard model: Z [variant prime] and neutrinos," Physical Review D , vol. 80, 2009.
[42] L. Basso, S. Moretti, G. M. Pruna, "A renormalisation group equation study of the scalar sector of the minimal B-L extension of the standard model," Physical Review D , vol. 82, 2010.
[43] F. Maltoni, K. Paul, T. Stelzer, S. Willenbrock, "Associated production of the Higgs boson and a single top quark at hadron colliders," Physical Review D , vol. 64, 2001.
[44] A. Belyaev, N. D. Christensen, A. Pukhov, "CalcHEP 3.4 for collider physics within and beyond the standard model," Computer Physics Communications , vol. 184, no. 7, pp. 1729-1769, 2013.
[45] J. Pumplin, D. R. Stump, J. Huston, H. L. Lai, P. M. Nadolsky, W. K. Tung, "New generation of Parton distributions with uncertainties from global QCD analysis," Journal of High Energy Physics , vol. 2002, article 07, 2002.
[46] K. A. Olive, K. Agashe, C. Amsler, "Review of particle physics," Chinese Physics C , vol. 38, no. 9, 2014.
[47] T. Robens, T. Stefaniak, "Status of the Higgs singlet extension of the standard model after LHC run 1," The European Physical Journal C , vol. 75, no. 3, article 104, 2015.
[48] L. Basso, S. Moretti, G. M. Pruna, "Theoretical constraints on the couplings of non-exotic minimal Z [variant prime] bosons," Journal of High Energy Physics , vol. 2011, no. 8, article 122, 2011.
[49] L. Basso, A. Belyaev, S. Moretti, G. M. Pruna, "Tree-level unitarity bounds for the minimal B-L model," Physical Review D , vol. 81, no. 9, 2010.
[50] S. Banerjee, M. Mitra, M. Spannowsky, "Searching for a heavy Higgs boson in a Higgs-portal B-L model," Physical Review D , vol. 92, 2015.
[51] L. Basso, S. Moretti, G. M. Pruna, "Phenomenology of the minimal B-L extension of the Standard Model: the Higgs sector," Physical Review D , vol. 83, 2011.
[52] J. Alwall, R. Frederix, S. Frixione, "The automated computation of tree-level and next-to-leading order differential cross sections, and their matching to parton shower simulations," Journal of High Energy Physics , vol. 2014, no. 7, article 079, 2014.
[53] T. Sjöstrand, S. Mrenna, P. Skands, "PYTHIA 6.4 physics and manual," Journal of High Energy Physics , vol. 2006, no. 5, article 026, 2006.
[54] J. de Favereau, C. Delaere, P. Demin, "DELPHES 3: a modular framework for fast simulation of a generic collider experiment," Journal of High Energy Physics , vol. 2014, no. 2, article 57, 2014.
[55] G. Aad, B. Abbott, J. Abdallah, "Search for the standard model Higgs boson produced in association with top quarks in proton-proton collisions at s=7 TeV using the ATLAS detector," ATLAS-CONF-2012-135
[56] S. Chatrchyan, G. Hmayakyan, V. Khachatryan, "Search for Higgs boson production in association with top quark pairs in pp collisions," CMS-PAS-HIG-12-025
[57] N. Arkani-Hamed, T. Han, M. Mangano, L.-T. Wang, "Physics opportunities of a 100 TeV proton-proton collider," https://arxiv.org/abs/1511.06495
You have requested "on-the-fly" machine translation of selected content from our databases. This functionality is provided solely for your convenience and is in no way intended to replace human translation. Show full disclaimer
Neither ProQuest nor its licensors make any representations or warranties with respect to the translations. The translations are automatically generated "AS IS" and "AS AVAILABLE" and are not retained in our systems. PROQUEST AND ITS LICENSORS SPECIFICALLY DISCLAIM ANY AND ALL EXPRESS OR IMPLIED WARRANTIES, INCLUDING WITHOUT LIMITATION, ANY WARRANTIES FOR AVAILABILITY, ACCURACY, TIMELINESS, COMPLETENESS, NON-INFRINGMENT, MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. Your use of the translations is subject to all use restrictions contained in your Electronic Products License Agreement and by using the translation functionality you agree to forgo any and all claims against ProQuest or its licensors for your use of the translation functionality and any output derived there from. Hide full disclaimer
Copyright © 2016 Bingfang Yang et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. The publication of this article was funded by SCOAP3 .
Abstract
We study the single top production in association with a Higgs boson in the U(1[subscript])B-L[/subscript] extension of the Standard Model at the LHC. We calculate the production cross sections of the processes pp[arrow right]thX (h=[subscript]H1[/subscript] ,[subscript]H2[/subscript] ; X=j,b,W) in this model. We further study the observability of the process pp[arrow right]t[subscript]H2[/subscript] j through pp[arrow right]t([arrow right]q[superscript]q-[variant prime][/superscript] b)[subscript]H2[/subscript] ([arrow right]4l)j and find that it is still challenging for the 14 TeV LHC with high luminosity to detect this signal.
You have requested "on-the-fly" machine translation of selected content from our databases. This functionality is provided solely for your convenience and is in no way intended to replace human translation. Show full disclaimer
Neither ProQuest nor its licensors make any representations or warranties with respect to the translations. The translations are automatically generated "AS IS" and "AS AVAILABLE" and are not retained in our systems. PROQUEST AND ITS LICENSORS SPECIFICALLY DISCLAIM ANY AND ALL EXPRESS OR IMPLIED WARRANTIES, INCLUDING WITHOUT LIMITATION, ANY WARRANTIES FOR AVAILABILITY, ACCURACY, TIMELINESS, COMPLETENESS, NON-INFRINGMENT, MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. Your use of the translations is subject to all use restrictions contained in your Electronic Products License Agreement and by using the translation functionality you agree to forgo any and all claims against ProQuest or its licensors for your use of the translation functionality and any output derived there from. Hide full disclaimer