118438822
Dark matter and Higgs phenomenology predicted by left-right twin Higgs model in light of CDMS II results
The left-right twin Higgs model predicts a light stable scalar Ŝ, which is a candidate for WIMP dark matter. We study its scattering on nucleon and find that the cross section is below the CDMS II upper bound but can reach the SuperCDMS sensitivity. Then we study the Higgs phenomenology by paying special attention to the decay h → ŜŜ which is strongly correlated with the dark matter scattering on nucleon. We find that such an invisible decay can be sizable, which can severely suppress the conventional decay modes like h → VV (V = W, Z) and $ h \to b\bar b $. On the other hand, compared to the SM prediction, the rates of Higgs boson productions at the LHC via gluon-gluon fusion, weak boson fusion or in association with top quark pairs are all reduced significantly, e.g., the gluon-gluon fusion channel can be suppressed by about 30%.
119209933
Higgs boson production in photon-photon collision at ILC: a comparative study in different little Higgs models
We study the process $ \gamma \gamma \to h \to b\bar b $ at ILC as a probe of different little Higgs models, including the simplest little Higgs model (SLH), the littlest Higgs model (LH), and two types of littlest Higgs models with T-parity (LHT-I, LHT-II). Compared with the Standard Model (SM) prediction, the production rate is found to be sizably altered in these little Higgs models and, more interestingly, different models give different predictions. We find that the production rate can be possibly enhanced only in the LHT-II for some part of the parameter space, while in all other cases the rate is suppressed. The suppression can be 10% in the LH and as much as 60% in both the SLH and the LHT-I/LHT-II. The severe suppression in the SLH happens for a large tan β and a small mh, in which the new decay mode h → ηη (η is a light pseudo-scalar) is dominant; while for the LHT-I/LHT-II the large suppression occurs when f and mh are both small so that the new decay mode h → AHAH is dominant. Therefore, the precision measurement of such a production process at the ILC will allow for a test of these models and even distinguish between different scenarios.
118798405
Two Higgs bidoublet model with spontaneous P and CP violation and decoupling limit to the two Higgs doublet model
The two Higgs bidoublet left-right symmetric model (2HBDM) as a simple extension of the minimal left-right symmetric model with a single Higgs bidoublet is motivated to realize both spontaneous parity (P) violation and charge conjugation and parity (CP) violation while consistent with the low-energy phenomenology without significant fine-tuning. By carefully investigating the Higgs potential of the model, we find that sizable CP-violating phases are allowed after the spontaneous symmetry breaking. The mass spectra of the extra scalars in the 2HBDM are significantly different from the ones in the minimal left-right symmetric model. In particular, we demonstrate in the decoupling limit when the right-handed gauge-symmetry-breaking scale is much higher than the electroweak scale, the 2HBDM decouples into the general two Higgs doublet model with spontaneous CP violation and has rich induced sources of CP violation. We show that in the decoupling limit, it contains extra light Higgs bosons with masses around electroweak scale, which can be directly searched at the ongoing LHC and future International Linear Collider experiments.
119246009
What if bb does not dominate the decay of the Higgs-like boson?
The dominant decay mode of standard model Higgs at 126 GeV $b\bar{b}$ suffers from severe SM background at the LHC even in associated productions $Wh_{\rm SM}$ or $Z h_{\rm SM}$. The precision measurement of BR($\phi\to b\bar{b})$ requires more data to reduce its large error bar. We investigate the possibility of this channel with largest uncertainty not dominating the decay of Higgs-like boson discovered at the LHC. In such scenarios, the Higgs signal shows highly suppressed $b\bar{b}$, slightly reduced $\tau^{+}\tau^{-}$ and moderately enhanced gauge bosons comparing with the SM predictions. The model requires two different sources of electroweak symmetry breaking and radiative correction to $m_{b}$ strongly enhanced. However, large reduction in $b\bar{b}$ usually results large enhancement in $\tau^{+}\tau^{-}$ mode in particular. The reduction of $\tau^{+}\tau^{-}$ therefore implies that a new decay mode is inevitable. We find that a non-decoupling MSSM Higgs decay into lighter Higgs $H\to hh$ may fit the signature. Here, MSSM $H$ is identified as the 126 GeV resonance while $h$ is below $M_{H}/2$ and can evade the direct search bound at LEPII and Tevatron. Large $PQ$ and $R$ symmetry breaking effects mediated by strong interaction can strongly enhance radiative corrections in $m_b$. However, the scenario can only be realized in highly fine-tuned parameter region where $G_{Hhh}$ is tiny. Nevertheless, we discuss the discovery potential of this highly fine-tuned $H\to hh$ at the LHC.
116009345
Measurements of $\psi^\prime \to \bar{p} K^+ \Sigma^0$ and $\chi_{cj} \to \bar{p} K^+ \Lambda$
Using a sample of 1.06 x 10(8) psi' mesons collectedwith the BESIII detector at the BEPCII e(+)e(-) collider and chi(cJ) mesons produced via radiative transitions from the psi', we report the first observation for psi' -> (p) over barK(+)Sigma(0) + c.c. (charge conjugate), as well as improved measurements for the chi(cJ) hyperon decays chi(cJ) -> (p) over barK(+) Lambda + c.c. The branching fractions are measured to be B(psi' -> (p) over barK(+) Sigma(0) + c.c) = (1.67 +/- 0.13 +/- 0.12) x 10(-5), B(chi(c0) -> (p) over barK(+) Lambda + c.c) = (13.2 +/- 0.3 +/- 1.0) x 10(-4), B(chi(c1) -> (p) over barK(+) Lambda + c.c) = (4.5 +/- 0.2 +/- 0.4) x 10(-4), and B(chi(c2) -> (p) over barK(+) Lambda + c.c) = (8.4 +/- 0.3 +/- 0.6) x 10(-4), where the first error is statistical, and the second is systematic. In the decay of chi(c0) -> (p) over barK(+) Lambda + c.c:, an anomalous enhancement near threshold is observed in the invariant mass distribution of (p) over bar Lambda + c.c:, which cannot be explained by phase space. DOI: 10.1103/PhysRevD.87.012007
122909812
Precision measurements of B[ψ(3686)→π+π-J/ψ] and B[J/ψ→l+l-]
Based on (106.41 +/- 0.86) x 10(6) psi(3686) events collected with the BESIII detector at the BEPCII collider, the branching fractions of psi(3686) -> pi(+)pi(-)J/psi, J/psi -> e(+)e(-), and J/psi -> mu(+)mu(-) are measured. We obtain B[psi(3686) -> pi(+)pi(-)J/psi] = (34.98 +/- 0.02 +/- 0.45)%, B[J/psi -> e(+)e(-)] = (5.983 +/- 0.007 +/- 0.037)%, and B[J/psi -> mu(+)mu(-)] = (5.973 +/- 0.0007 +/- 0.038)%. The measurement of B[psi(3686) -> pi(+)pi(-)J/psi] confirms the CLEO-c measurement, and is apparently larger than the others. The measured J/psi leptonic decay branching fractions agree with previous experiments within one standard deviation. These results lead to B[J/psi -> l(+)l(-)] = (5.978 +/- 0.005 +/- 0.040)% by averaging over the e(+)e(-) and mu(+)mu(-) channels and a ratio of B[J/psi -> e(+)e(-)]/B[J/psi -> mu(+)mu(-)] = 1.0017 +/- 0.0017 +/- 0.0033, which tests e- mu universality at the four tenths of a percent level. All the measurements presented in this paper are the most precise in the world to date.
111596591
E823 (D0 upgrade): Magnetic tracking